I2B3 


DUTY  OF  WATER 

INVESTIGATIONS 


BV 


DON  PL  BARK 


IRRIGATION    ENGINEER 


i.NT  CHARGE  OF  IRRIGATION  INVi         'GATIQNS  IN  IDAHO, 

OFFICE  OF  EXPERIMEN  ^IONS, 

U    S.  DEPARTMENT   OF   A.  '  TURE. 


(The  work  upon  which  this  report  is  based  •\  done  under  a 

co-operative  agreement  between  the  Idaho  State  ^ard  of  Laud 

Commissioners  and  the  Office  of   Experiment   i  PUS,  United 
States  Department  of  Agriculture. 


DUTY  OF  WATER 

INVESTIGATIONS 


DON  H.  BARK 

IRRIGATION    ENGINEER 


IN  CHARGE  OF  IRRIGATION  INVESTIGATIONS  IN  IDAHO. 

OFFICE  OF  EXPERIMENT  STATIONS, 
U.  S.  DEPARTMENT    OF    AGRICULTURE. 


(The  work  upon  which  this  report  is  based  was  done  under  a 
co-operative  agreement  between  the  Idaho  State  Board  of  Land 
Commissioners  and  the  Office  of  Experiment  Stations,  United 
States  Department  of  Agriculture. 


e  3 


,^  :-»*s^5  V  ";  •  ,<!:•*>  ^ 


DUTY  OF  WATER  INVESTIGATION 

BY  !     I    >  \'   ' 

DON  H.  BARK./'' 

IRRIGATION    ENGINEER,    IN    CHARGE  OF    IRRIG'Al^ON' 'INVESTIGATIONS  °lW 

IDAHO.      OFFICE  OF  EXPERIMENT  STATIONS,  U.  S.   DEPARTMENT 

OF  AGRICULTURE. 


The  Idaho  State  Board  of  Land  CommiSvsi oners  entered 
into  a  co-operative  agreement  with  the  Irrigation  Investi- 
gations of  the  Office  of  Experiment  Stations,  U  S.  De- 
partment of  Agriculture,  late  in  the  fall  of  1909  for  the 
purpose  of  conducting  a  Duty  of  Water  investigation  in 
Idaho.  This  agreement  was  renewed  from  year  to  year,  the 
investigation  having  been  conducted  uninterruptedly  dur- 
ing the  seasons  of  1910,  11,  12,  and  13.  The  agreement  un- 
der which  the  investigation  was  carried  on  provided  that 
both  parties  should  contribute  equal  amounts  toward  the 
investigation;  that  the  plans  for  the  investigation  be  made 
and  agreed  upon  by  the  Idaho  State  Engineer  and  the 
chief  of  Irrigation  Investigations  of  the  U.  S.  Department 
of  Agriculture,  and  that  the  Idaho  Agent  of  Irrigation 
Investigations  should  be  charged  with  the  carrying  out  of 
the  investigation.  The  investigation  has  proved  to  be  very 
popular  with  the  irrigators  of  Idaho,  eight  of  the  larger  ir- 
rigation companies  of  the  State  having  contributed  to  the 
fund  set  aside  for  the  purpose  a  total  of  almost  f 8,000.00 
during  the  four  years  in  order  that  the  investigation  might 
be  extended.  The  reports  of  the  investigation  have  also 
been  much  sought  after,  the  demand  during  the  past  two 
years  having  far  exceeded  the  available  supply.  The  fol- 
lowing report  is  based  upon  the  results  of  the  investigation 
during  the  four  years,  1910  to  1913  inclusive,  the  investiga- 
tion having  covered  the  greater  part  of  irrigated  Idaho  dur- 
ing the  period. 

"Duty  of  Water"  is  a  term  that  is  used  to  express  the  re- 
lationship that  exists  between  a  given  quantity  of  irrigation 
water  and  the  area  of  land  it  is  made  to  servo.  The  Duty 
is  said  to  be  high  when  a  given  quantity  of  water  serves  a 
comparatively  large  area  of  land,  and  low  when  it  is  made 
to  serve  only  a  comparatively  small  area,  i.  c.,  the  Duty 
is  the  work  the  water  is  made  to  do.  It  is  evident  even  to 


64;:  REPORT  OF  STATE  ENGINEER. 

those  unfamiliar  with  irrigation  that  different  types  of 
land  and  different  kinds  of  crops  will  require  different 
ainoi^ts  of  water, -jand  that  all  water  rights  should  consist 
of  amounts  thaHt  -would  supply  the  actual  requirements  of 
.£he.$oife  and ; crops  in  question  and  no  more.  The  above  is 
correct  in  theory",  '"for  a'he  present  area  of  arid  land  is  fully 
twenty  times  that  of  the  irrigated  land,  but  to  work  it 
out  in  actual  practice  is  a  very  difficult  matter. 

Forty  years  ago  there  was  but  litle  irrigated  land  in 
Idaho,  water  was  plentiful  and  the  early  settlers  knew 
nothing  of  the  water  requirements  of  soils  and  crops.  They 
therefore  filed  upon  and  appropriated  abnormally  large 
amounts  for  the  irrigation  of  their  land  in  order  to  be  sure 
of  a  sufficient  amount.  As  time  passed  and  settlement  in- 
creased a  better  knowledge  of  the  water  requirements  of 
soils  was  obtained,  but  even  as  late  as  ten  years  ago  there 
was  no  real  definite  knowledge  of  nor  standard  practice 
in  regard  to  the  subject.  Water  rights  of  all  kinds  and 
sizes  existed.  The  need  for  definite  knowledge  of  the 
proper  amount  of  water  to  allot  under  different  conditions 
became  very  urgent  when  the  larger  projects  were  pro- 
posed. It  was  realized  that  if  too  small  an  amount  of 
water  was  allotted  the  settlers  would  suffer  because  of  de- 
creased crop  production,  while  if  more  than  enough  was 
allotted  the  land  would  become  water  logged  and  useless 
from  over  irrigation  and  the  ultimate  irrigated  area  would 
be  unnecessarily  reduced.  There  had  never  been  a  broad 
and  comprehensive  investigation  of  this  subject  and  the 
urgent  need  for  this  knowledge  as;  a  protection  to  the  set- 
tlers and  the  State  were  the  prime  factors  which  led  up  to 
the  investigation  herein  described. 

GENERAL  PLAN  AND  METHOD  OF  THE  INVESTI- 
GATION. 

Previous  investigations  of  the  subject  were  few  in  num- 
ber and  rather  confined  in  character.  The  majority  of  the 
investigations  that  had  been  made  prior  to  the  initiation 
of  the  investigation  herein  described  were  confined  chiefly 
to  the  mere  measurement  of  the  amounts  applied  to  crops 
by  irrigation  farmers  and  others.  Tfhe  various  Western 
State  Experiment  Stations  had  also  carried  on  some  in- 
vestigations of  this  subject  but  these  investigations  were 
necessarily  confined  to  comparatively  small  areas  on  the 


REPORT  OF  STATE  ENGINEER.  '65 

Experiment  Station  Farms.-  In  laying  plans  for  the  pres- 
ent investigation  it  was  plain  to  the  author  that  if  de- 
pendable data  for  use  in  connection  with  the  allotment 
of  water  to  large  projects  was  to  be  secured  (1)  that  an 
investigation  of  a  broad  character  must  be  carried  on; 
(2)  that  all  of  the  various  staple  farm  crops  must,  be 
included;  (3)  that  water  must  be  measured  upon  rather 
large  tracts;  (4)  that  only  such  tracts  as  were  typical  as 
regards  soil,  topography,  preparation  of  land,  etc.,  should 
be  included,  for  the  ultimate  results  secured  must  be 
such  as<  good  farmers  could  obtain  in  actual  practice;  (5) 
that  the  mere  measurement  of  water  applied  to  a  single 
tract  and  the  yields  secured  from  it  would  be  insufficient 
data  for  they  would  throw  no  light  upon  the  proper  Duty, 
for  there  would  be  no  indication  as  to  what  results  might 
have  been  secured  from  the  application  of  a  larger  or 
smaller  quantity  of  water. 

It  seemed  imperative  that  the  investigation  be  conducted 
in  such  a  way  that  the  results  would  be  practical,  fair,  and 
impartial,  and  that  they  could  be  used  with  safety  in  de- 
termining the  irrigation  requirements  of  a  large  project. 
It  was  realized  that  there  was  a  great  variation  Jn  ^oijs 
and  crops,  and  even  between  the  irrigators  themselves,  as 
well  as  between  different  seasons^  and  it  seemed  plain  that 
a  large  number  of  tracts  should  be  included,  and  that  the 
investigation  be  made  to  extend  over  a  number  of  years 
if  dependable  data  were  to  be  secured. 

It  was  therefore  decided  at  the  outset  that  the  investiga- 
tion should  include  all  of  the  staple  farm  crops  common 
to  South  Idaho,  and  that  the  water  should  be  measured 
upon  comparatively  large  areas.  Tfracts  consisting  of  ap- 
proximately 15  acres  were  fixed  as  a  basis,  .care  being  used 
to  select  only  such  tracts  as  had  uniform  soil  conditions, 
stand  of  crop,  and  previous  preparation  throughout.  It 
was  decided  to  include  only  typical  tracts  selected  from 
average  farmers-  farms,  and  that  each  15  acre  tract,  when- 
ever possible,  should  be  divided  into  three  parts,  that  the 
farmer  or  owner  should  be  allowed  to  select  one  of  the  three 
plots  into  which  his  tract  was  divided  and  to  irrigate  it 
during  the  season  according  to  his  own  ideas,  following 
his  usual  custom  in  regard  to  the  time  and  amount  of 
irrigation.  The  amount  applied  by  the  owner  was  to.]b,e 
measured  very  carefully  by  one  of  the  author's  assistants 
each  time  the  land  was  irrigated,  and  the  other  two  plots 


66  REPORT  OF  STATE  ENGINEER. 

were  to  be  irrigated  during  the  season  by  applying  a  greater 
amount  to  one  and  a  less  amount  to  the  other  than  the 
owner  used  upon  the  plot  which  he  himself  had  selected. 
Thus  there  were  in  almost  every  case  three  tracts  of  the 
same  crop,  each  tract  consisting  of  an  area  of  about  5  acres 
with  uniform  soil  conditions  and  previous  preparation 
throughout,  to  which  three  different  amiounts  of  water 
were  applied  during  the  season.  The  water  applied  to  and 
wasted  from  the  tracts,  the  areas  and  yields,  were  all  very 
carefully  determined,  and  it  was  rather  easy  to  decide  in 
the  fall  from  the  yield  produced  which  tract  had  received 
the  best  amount  of  water  for  the  soil  and  crop  in  question. 
A  portion  of  the  experiments  included  in  the  investigation 
has  been  made  at  the  Gooding  Experiment  Station,  this 
station  being  conducted  jointly  by  the  Irrigation  Investi- 
gations and  the  Idaho  Experiment  Station  of  the  State 
Agricultural  College. 

Scope  of  Investigation. 

The  investigation  has  covered  the  seasons  of  191 0,  1911, 
1912,  and  1913,  during  which  time  water  has  been  meas- 
ured accurately  upon  a  total  of  approximately  529  indivi- 
dual plots  or  tracts,  ranging  in  size  from  .10  of  an  acre  up 
to  over  150  acres,  and  consisting  of  a  total  area  of  slightly 
over  3,600  acres.  All  of  the  areas  involved  have  been  care- 
fully surveyed  with  a  transit,  and  the  measurement  of  the 
water  applied  to  over  two-thirds  of  the  tracts  experimented 
upon,  has  been  made  by  our  own  assistants,  who  have  been 
on  the  ground  during  the  entire  time  of  each  irrigation. 
The  water  applied  to  the  remainder  of  the  tracts  included 
in  the  investigation  has  been  measured,  (1)  by  automatic 
water  registers,  (2)  by  the  owners  themselves,  or  (3)  by  an 
assistant  who,  during  the  season  of  1912,  was  employed  to 
read  a  large  number  of  weirs  twice  daily. 

The  results  secured  from  a  small  proportion  of  the  ex- 
periments have  been  found  to  be  in  error,  due  to  accidents 
and  a  variety  of  other  unavoidable  circumstances.  These 
have  been  discarded  and  nothing  has  been  included  in  this 
report  that  is  not  absolutely  dependable. 

The  investigation  has  covered  a  wide  scope  of  territory, 
the  experiments  having  been  scattered  from  Weiser,  with 
an  altitude  of  2,114  feet,  situated  on  the  bank  of  Snake 
River  on  the  Oregon  Line,  to  Rigby,  with  an  altitude  of 
4,950  feet,  in  the  upper  Snake  River  Valley,  350  miles  east- 
ward from  Weiser. 


REPORT  OF  STATE  ENGINEER.  67 

Alfalfa,  clover,  pasture,  oats,  wheat,  barley,  rye,  pota- 
toes and  orchard,  the  staple  crops  of  South  Idaho,  have  all 
been  represented,  but  the  majority  of  the  experiments  have 
been  conducted  with  alfalfa  and  the  grains. 

The  average  soil  of  South  Idaho  is  a  "lava  ash"  or  me- 
dium clay  loam,  rich  in  lime  and  mineral  plant  foods, 
but  deficient  in  nitrogen  in  its  raw  state.  This  soil  ranges 
in  depth  from  two  to  forty  feet,  with  a  probable  average 
of  slightly  over  four  feet,  and  is  well  adapted  for  irrigation, 
being,  as  a  rule,  very  uniform  in  texture  and  composition 
throughout  its  entire  depth. 

While  the  majority  of  the  experiments  have  been  con- 
ducted upon  the  average  soil,  the  investigation  has  covered 
such  a  large  number  of  tracts  scattered  over  so  wide  an 
area  that  nearly  all  types  of  soil  ranging  from  the  finest 
of  adobe  clays  to  the  coarsest  of  gravels  have  been  well 
represented. 

It  was  decided  at  the  outset  that  the  total  amount  of 
water  that  would  be  required  by  any  project  would  depend 
upon  the  following  factors : 

( 1 )  Gross  area  of  project. 

(2)  Duty  of  water  at  the  land. 

(3)  The  amount  of  loss  that  the  irrigation  water  would 
be  subjected  to  in  transmitting  it  from  the  point  of  diver- 
sion to  the  land  to  be  irrigated. 

(4)  The  amount  of  loss  through  both  evaporation  and 
seepage  from  reservoirs,  if  any  were  necessary  in  connec- 
tion with  the  system. 

(5)  The  proportion  of  a  project  that  is  ultimately  irri- 
gated. 

It  was  therefore  deemed  necessary  in  connection  with  the 
investigation  to  investigate  the  seepage  losses  of  typical 
Idaho  canals  and  to  survey  a  large  amount  of  land  in- 
cluded in  well-developed  typical  irrigation  projects  to  de- 
termine just  what  per  cent  was  unirrigated.  A  seepage 
investigation  was  conducted  during  the  two  latter  years 
of  the  investigation,  58  sections  of  different  canals  with  an 
aggregate  length  of  109.2  miles  having  been  measured  in 
1912,  and  60  sections  of  different  canals  with  an  aggregate 
length  of  178.11  miles  having  been  measured  during  the 
season  of  1913.  The  canals  measured  varied  in  discharge 
from  0.07  cu.  ft.  per  second  to  over  3,190.0  cu.  ft.  per 
second,  and  in  cross-section  from  0.117  sq.  ft,  to  984.0  sp.  ft. 

The  survey  of  irrigated  land  for  the  determination  of  the 


68  REPORT  OF  STATE  ENGINEER. 

percentage  of  waste  and  non-irrigated  laud  in  a  typical  pro- 
ject was  conducted  during  the  season  of  1913.  The  land 
surveyed  for  this  purpose  consisted  of  a  total  of  16,065.21 
acres,  part  of  which  was  located  near  Kimberly,  on  the 
South  Side  Twin  Falls  Ttract,  the  remainder  lying  under 
the  old  canals  in  the  Boise  River  Valley  adjacent  to  and 
tributary  to  the  town  of  Meridian.  The  land  surveyed 
was  typical  in  every  way  of  the  better  class  of  Idaho  irri- 
gated land  and  the  results  secured  may  be  used  with  im- 
punity as  a  basis  for  other  or  newer  projects. 

The  investigation  during  the  four  years  naturally  and 
necessarily  included  the  investigation  of  many  other  minor- 
subjects,  such  as  deep  percolation  on  gravelly  irrigated 
land,  a  study  of  rotation  systems  and  their  adaptability  to 
different  conditions,  a  study  of  the  cost  and  feasibility  of 
lifting  water  by  electric  motors  and  centrifugal  pumps,  and 
practically  all  other  minor  factors  wMch  it  was  believed 
might  have  a  bearing  on  the  duty  of  water. 

Measurement  of  Water. 

Cippoletti  weirs  were  used  for  the  measurement  of  all 
water  applied  to  the  experimental  tracts  throughout  the 
investigation,  carefully  constructed  weirs  having  been  in- 
stalled in  the  feed  ditches  leading  to,  and  in  the  waste1 
ditches  leading  from,  each  tract  for  the  purpose.  All 
of  the  amounts  tabulated  in  this  report  represent  only 
those  retained  upon,  or  absorbed  by,  the  tract,  the  waste 
having  been  deducted,  unless  otherwise  specified.  In 
nearly  all  cases  the  measurements  were  made  by  assistants 
employed  especially  for  the  purpose,  it  having  been  de- 
cided for  obvious  reasons  that  it  would  be  undesirable  to 
have  the  owner,  or  anyone  who  might  be  prejudiced  in 
favor  of  a  high  or  low  Duty,  connected  with  the  investiga- 
tion in  any  way.  The  head  on  the  weirs  was  measured 
by  the  assistant  or  assistants  in  charge  of  the  experiments 
as  often  as  was  considered  necessary.  Where  the  head  re- 
mained quite  uniform  it  was  measured  at  intervals  of  from 
one  to  two  hours.  Whenever  the  amount  of  water  and  con- 
sequent head  on  the  weirs  varied  or  fluctuated  to  any  ex- 
tent the  head  was  measured  more  frequently. 

The  Cippoletti  weir,  designed  by  the  Italian  engineer  of 
the  same  name,  was  used  exclusively  throughout  the  in- 
vestigation, great  care  being  used  to  secure  the  proper  con- 
ditions for  accurate  measurement.  The  formula  used  in 


REPORT  OF  STATE  ENGINEER.  69 

computing  the  discharge  of  these  weirs  was  Q  equals  3.367 
L.  H.  i 

Where  Q  equals  discharge  in  cubic  feet  per  second, 
L  equals  length  of  crest  in  feet,  and 
H  equals  head  or  depth  of  water  on  the  crest  in 
feet. 

The  above  is  the  formula  used  in  general  practice  for 
the  determination  of  the  discharge  over  this  type  of  weir 
and,  provided  certain  conditions  are  maintained,  has  been 
determined  to  be  within  one  per  cent  of  accurate  by  many 
long  series  of  complicated  experiments. 

The  conditions  which  must  obtain  to  insure  reasonable 
accuracy  of  measurement,  and  which,  as  near  as  possible, 
were  observed  throughout  the  investigation,  are: 

(1)  The  weir  proper  should  consist  of  a  notch,  trape- 
zoidal in  shape    and  thin  in  section,  preferably  cut  from 
a  piece  of  metal  such  as1  sixteen  gauge  galvanized  iron. 

(2)  The  bottom  edge  of  the  notch  should  be  a  straight 
line  either  one,  two,  or  three  feet  in  length,  or  longer,  de- 
pending upon  the  amount  of  water  required,  which  should 
govern  the  size  of  the  weir.     The  sides  of  the  notch  should 
slope  outward  at  the  rate  of  one  horizontally  to  four  ver- 
tically, thus  a  one  foot  Cippoletti  weir  should  have  a  bot- 
tom or  crest  length  of  exactly  one  foot  and  a  top  width, 
with  a  depth  of  six  inches,  of  fifteen  inches,  both  sides 
of  the  weir  sloping  outward  at  the  same  angle. 

(3)  All  water  to  be  measured  should  be  passed  through 
the  notch  or  over  the  weir.     The  notch  or  weir  must  be  set 
vertically  Avith  its  crest  or  bottom  in  a  horizontal  position, 
and  the  entire  plate  or  notch  should  be  perpendicular  to 
the  axis  of  the  stream. 

(4)  The  water  should  have  a  free  fall  over  the  weir, 
i.  e.y  the  water  below  the  weir  should  not  back  up  so  as  to 
drown  or  submerge  it.     There  should  be  enough  clearance 
so  that  air  can  circulate  freely  under  the  issuing  stream  at 
all  times. 

(5)  The  water   should   enter   the   weir  slowly,   being 
brought  to  a  state  of  rest  if  possible  before  entering  or 
passing  over  the  weir.     This  is  usually  secured  by  digging 
a  rather  deep,  wide  pool  above  the  weir  or  by  building  the 
weir  box  of  large  enough  cross  section  to  insure  a  slow 
"velocity  of  approach,"  which  is  very  necessary  if  accurate 
measurement  is  to  be  obtained. 

(6)  The  depth  of  water  flowing  over  the  crest  of  the 


70  REPORT   OF   STATE   ENGINEER. 

weir  should  not  be  measured  on  the  crest  but  from  a  point 
level  with  the  crest  and  up-stream  from  it,  a  distance  of 
about  twice  the  length  of  the  crest.  This  is  necessary,  as 
the  water  has  a  downward  curve  as  the  crest  is  approached, 
and  the  depth  moist  be  measured  from  still  water  if  the 
formula  is  to  give  accurate  measurement.  The  best  and 
most  common  method  of  setting  a  point  from  which  to 
measure  the  water,  and  the  one  that  was  used  throughout 
the  investigation,  is  to  set  a  heavy  2x4  or  4x4  peg  or  stake 
in  the  pool  up-stream  from  the  weir.  This  peg  should  be 
heavy  enough  so  that  it  cannot  be  readily  disturbed,  and 
should  be  driven  from  one-half  to  an  inch  below  the  level 
of  the  weir  crest.  A  heavy  nail  or  spike  should  then  be 
driven  vertically  into  the  top  of  the  stake,  the  upper  face 
of  the  spike  being  exactly  levelled  with  the  crest  of  the 
weir  by  means  of  a  carpenter's  or  engineer's  level,  the  weir 
having  previously  been  established  in  the  weir  box  both 
vertical  and  horizontal  and  at  right  angles  to  the  axis 
of  the  stream  entering  the  weir  box. 

The  head  on  the  weirs  was  measured  by  the  observers 
with  small  steel  rules  graduated  to  one-hundredth  of  a  foot. 
During  measurement  the  observer  held  his  eye  as  close  to 
the  surface  of  the  water  in  the  pool  as  possible  and  extend- 
ed the  thin  rule  down  through  the  water  to  the  head 
of  the  nail,  the  height  of  the  water  on  the  rule  being  noted, 
which  gave  the  correct  head  on  the  weir. 

(7)  The  depth  of  water  flowing  over  the  crest  should 
never  be  allowed  to  exceed  one-half  of  the  crest  length,  and 
it  is  preferable  that  it  should  not  exceed  one-third  of  the 
crest  length.  Where  it  is  desired  to  measure  so  much  water 
that  it  gives  too  great  a  depth  on  a  one-foot  weir,  a  two- 
foot  weir  or  a  three-foot  weir,  as  the  case  may  be,  should 
be  installed.  Accurate  measurement  demands  that  there 
should  never  be  less  than  one  inch  of  water  flowing  over 
the  crest.  This  is  necessary  in  order  to  secure  complete 
contraction  of  the  issuing  stream,  which  is  very  essential. 
Obstructions  of  any  kind  should  not  be  permitted.  The 
sides  of  the  weir  box  or  pool  should  never  approach  the 
sides  of  the  weir.  The  distance  between  the  edge  of  the 
issuing  stream  and  the  outer  edge  of  the  box  for  small  weirs 
should  always  be  at  least  twice  as  great  as  the  depth  of 
water  flowing  over  the  crest. 

It  has  been  determined  by  experiment  that  the  following 
conditions  are  necessary  if  a  slow  velocity  of  approach  is  to 


REPORT  OF  STATE  ENGINEER.  71 

be  secured  on  weirs.  These  conditions  are  not  ironclad, 
however,  and  may  be  varied  slightly,  the  slow  velocity  of 
approach  and  an  unobstructed  free  fall  of  the  issuing 
stream  being  the  things  most  of  all  desired.  The  cross  sec- 
tion of  the  stream  in  the  weir  box  or  in  the  pool  above  the 
weir  should  be  at  least  seven  times  as  great  as  that  of  the 
stream  which  issues  through  and  over  the  weir  crest.  The 
height  of  the  crest  above  the  bottom  of  the  box  or  pool 
should  be  at  least  twice  and  preferably  three  times  that  of 
the  depth  of  the  water  over  the  crest. 

In  order  to  better  illustrate  the  conditions  that  must  ob- 
tain for  accurate  measurement  and  the  conditions  that 
Avere  observed  throughout  the  Duty  of  Water  investigation, 
the  following  cut  of  an  ideal  weir  and  weir  box  are  in- 
serted : 


'•>  i  ,V/;. 

'•'"<*l'l  'i, 

-4^/-*V^W.. 

\v  •//>  v  /,  . ',      ''///  ,,/'//   i 

\  '     "   K  *»  '    "*        f  /   I  ti   '"          I/'     //  /'  //// 

;,^ix   \ti',y !•&,.. 

;/;;  iv^i^  "*  >»;^// 

y-     tww./l.>!lf-tjt'ijtl'l>;iv'i 

-.','  ;\    fm^h''A'';'! 
'  \:  ^Mf/J'Wfyj.ii, 

^^^r/^^y^?^^^^!^ 

^-^  J'  '\"W^^ 

&£'**» -    '  "•  A  \^%, tzf'^' , s,/:'// ''' , 

,  •   ^\    N  ^ZLrli&'tf'^tf'te' 

,  f  &       w/^/y ^ ;,/.  y<  /> o/ 
1 "  ,. ' - \      ^:<^^&-^^ 

\\  '    \^   \^^S^^fk 


^^'^/'y    H 
•  ^/^t^  ' 

fe&^A 


11 1 


REPORT  OP  STATE  ENGINEER.  73 

The  weir  box  shown  in  the  above  cut  is  no  part  of  the 
weir  proper  and  is  necessary  for  the  sole  and  only  purpose 
of  holding  the  weir  in  place  and  forcing  all  of  the  water  to 
pass  over  it  without  leakage.  Some  writers  insist  on  longer 
boxes  or  boxes  of  specific  dimensiop,  but  these  dimensions 
have  been  arrived  at  and  are  given  in  order  to  insure  a  suf- 
ficient size  of  cross  section  to  insure  free  fall  over  the 
weir,  complete  contraction  of  the  issuing  stream,  and  a 
slow  velocity  of  approach.  The  above  canditions  may  be 
obtained,  including  a  slow  velocity  of  approach,  if  the  fore- 
going instructions  are  carefully  observed,  and  a  compara- 
tively deep,  wide  pool  is  maintained  in  the  ditch  above  the 
weir  box. 

The  following  table  has  been  compiled  for  the  use  of 
irrigation  farmers  and  others,  the  depths  on  the  crest  be- 
ing given  in  inches  and  fractions  of  an  inch  rather  than  in 
hundredths  of  a  foot  in  order  that  the  irrigators  may  use 
the  table  in  connection  with  the  ordinary  rules  in  com- 
mon use,  such  as  school  rulers,  yard  sticks,  carpenter's 
rules,  or  squares  instead  of  special  rules  graduated  to  hun- 
dredths of  a  foot,  which  are  not  commonly  accessible.  This 
table  gives  the  discharge  over  the  smaller  sizes  of  weirs 
both  in  cubic  feet  per  second  and  in  Idaho  miner's  inches, 
of  which  there  are  fifty  in  a  "second  foot." 


74  REPORT  OF  STATE  ENGINEER. 

DISCHARGE  OF  CIPPOLETTI  WKIRS  IN  IDAHO  MINER'S  INCHES 
AND  SECOND  FEET. 


Depth 
of 
water  on 
crest 
—inches 

One-foot  weir 

Two-foot  weir 

Three-foot  weir 

Second 
feet 

.010 
.029 
.053 
.081 
.113 
.149 
.188 
.229 
.273 
.320 
.369 
.421 
.474 
.531) 
.588 
.648 
.709 
.773 
.839 
.906 
.974 
1.044 
1.116 
1.191 

Miner's 
inches 

Second 
feet 

.020 
.058 
.106 
.162 
.226 
.298 
.376 
.458 
.546 
.640 
.,38 
.812 
.948 
1.060 
1.176 
1.296 
1.418 
1.546 
1.678 
1.812 
1.948 
2.088 
2.232 
2.382 
2.531 
2.684 
2.841 
3.  COO 
3.162 
3.327 
3l%96 
3.664 
3.838 
4.014 
4.192 
4.374 
4.557 
4.744 
4.932 
5J24 
5.316 
5.510 
5,709 
5.910 
6.112 
6.317 
6.525 
6.734 

Miner's 
inches 

Second 
feet 

Miner's 
inches 

% 

J/a 

*4 

1 

o% 

\ 
Va 
% 
3 

g 

% 

4 

tt 

* 

% 

e^ 
| 

% 

1 

£ 

% 

9 
% 

J 
) 

| 

«* 

0.5 
1.6 

2.7 
4.1 
5.7 
7.5 

9.4 
U.5 
13.7 
16.0 

18.5 
21.1 
23.7 
26.5 
29.4 
32.4 
35.5 
38.7 
42.0 
45.3 
48.7 
52.2 
55.8 
59.6 

1.0 

2.y 

5.3 

8.1 
11.3 
14.9 
18.8 
22.9 
27.3 
32.0 
36.9 
42.1 
47.4 
53.0 
58.8 
64.8 
70.9 
77.3 
83.9 
90.6 
97.4 
104.4 
111.6 
119.1 
126.6 
134.2 
142.1 
150.0 
158.1 
166.4 
174.8 
183.2 
191.9 
200.7 
209.6 
218.7 
227.9 
237.2 
246.6 
256.2 
265.8 
275.5 
285.5 
295.5 
305.6 
315.9 
326.3 
336.7 

.030 
.087 
.159 
.243 
.339 
.447 
.564 
.687 
.819 
.960 
1.107 
1.263 
1.422 
1.590 
1.764 
1.944 
2.127 
2.319 
2.517 
2.718 
2.922 
3.132 
3.348 
3.573 
3.796 
4.026 
4.261 
4.500 
4.743 
4.990 
5.244 
5.496 
5.757 
6.021 
6.288 
6.561 
6.835 
7.116 
7.398 
7.686 
7.974 
8.265 
8.563 
8.865 
9.168 
9.475 
9.787 
10.101 
1 

1.5 
4.4 
8.0 
12.2 
17.0 
22.4 
28.2 
34.4 
41.0 
48.0 
55.4 
63.2 
71.1 
79.5 
88.2 
97.2 
106.4 
116.0 
125.9 
135.9 
146.1 
156.6 
167.4 
178.7 
189.8 
201.3 
213.1 
225.0 
237.1 
249.5 
262.2 
274.8 
287.9 
301.1 
314.4 
328.0 
341.8 
355.8 
369.9 
384.3 
398.7 
413.3 
428.2 
443.2 
458.4 
473.9 
489.4 
505.0 

. 

The  above  table  gives  the  discharge  of  the  smaller  sizes 
of  Cippoletti  w^irs  in  cubic  feet  per  second  and  in  Idaho 
miner's  inches,  but  is  not  of  much  use  to  the  ordinary  ir- 
rigator  in  determining  the  exact  depth  or  quantity  that 
he  has  applied  to  his  land  in  acre  feet.  For  the  use  of 
those  who  care  to  calculate  the  amounts  that  have  been 
applied  either  as  acre  feet  or  as  depths  on  the  land,  the  fol- 
lowing table  is  included,  it  having  been  devised  to  facili- 
tate the  enormous  amount  of  computation  in  connection 
with  the  four  seasons'  Duty  of  Water  Investigation.  From  it 


REPORT  OF  STATE  ENGINEER. 


75 


may  be  obtained  the  number  of  acre  feet  or  fraction  of  an 
acre  foot  per  hour  that  will  be  discharged  over  the  smaller 
sizes  of  Cippoletti  weirs  such  as  will  be  used  in  common 
practice.  In  illustration  of  its  use  it  will  be  seen  from 
the  table  that  a  depth  of  three  inches  or  0.25  feet  over  a 
one  foot  Cippoletei  weir  will  discharge  .0348  acre  feet  per 
hour,  or  .348  acre  feet  in  ten  hours,  or  3.48  acre  feet  in  one 
hundred  hours,  which  would  cover  one  acre  3.48  feet  deep 
in  100  hours. 

DISCHARGE  OF  CIPPOI^ETTI  WEIRS  IN  ACRE  FEET  PER  HOUR. 


u 

Acre  feet 

V*  '  • 

l| 

Acre  feet 

Ui 

a>  -g 

Acre 

|| 

Acre 

•  v< 

>  *2^ 

feet  in  one 

feet  in  one 

S-,   ' 

in  one  hour 

M-i  -i 

in  one  hour 

<«H  -i 

hour 

<4*  -i 

hour 

"o  jo 

o  « 

"o  « 

"Q  to 

(U 

u 

u 

u 

J3  S 

u 

V- 

0) 

•*-»  o 

u 

w 

J3  <- 

u 

u 

f« 

<+H  '£ 

sl 

si 

& 

'V  '<u 

si 

31 

si 

**?  '3 

is 

"V  '5 

si 

1 

1 

.011  .0003 

.0006 

.0008 

.26 

.0369 

.0738 

.1107 

.51 

.2027 

.3040 

.76 

.3687 

.5530 

.02 

.0008 

.0016 

.0024 

.27 

.0390 

.0781 

.1171 

.52 

.2087 

.3130 

.77 

.3760 

.5640 

.03 

.0014 

.0029 

.0043 

.28 

.0412 

.0824 

.1237 

.53 

.2147 

.3221 

.78 

.3833 

.5750 

.04 

.0022 

.0045 

.0067 

.29 

.0435 

.0869 

.1304 

.54 

.2208 

.3312 

.79 

.3907 

.5861 

.051  .0031 

.0062 

.0093 

.30 

.0457 

.0914 

.1372 

.55 

.2270 

.3405 

.80 

.3982 

.5973 

.06 

.0041 

.0082 

.0123 

.31 

.0480 

.0960 

.1441 

.56 

.2332 

.3498 

.81 

.4057 

.6085 

.07|  .0052 

.0103|  .0155 

.32 

.0504 

.1007 

.1511 

.57 

.2395 

.3592 

.82 

.4132 

.6198 

.081  .0063 

.0126  .0189 

.33 

.0527 

.1055 

.1582 

.58 

.2458 

.3687 

.83 

.4208 

.6312 

.09 

.ixu5 

.0150  .0225 

.34 

.0552 

.1103 

.1655 

.59 

.2522 

.3783 

.84 

.4284 

.6426 

.101  .0088 

.0176  .0264 

.35 

.0576 

.1152 

.1728 

.60 

.2586 

.3879 

.85 

.4361 

.6541 

.11 

.0102 

.02031  .0305 

.36 

.0601 

.1202 

.1803 

.61 

.2651 

.3977 

.86 

.4438 

.6657 

.12!  .0116 

.0231 

.0347 

.37 

.0626 

.1252 

.1879 

.62 

.2717 

.4075 

.87 

.4516 

.6774 

.13 

.0130 

.0261 

.0391 

.38 

.0652 

.1304 

.1955 

.63 

.2783 

.4174 

.88 

.4594 

.6891 

.14J  .0146 

.0291 

.0437 

.39 

.0678 

.1355 

.2033 

.64 

.2849 

.4274 

.89 

.4672 

.7008 

.15 

.0162 

.0323 

.0485 

.40 

.0704 

.1408 

.2112 

.65 

.2916 

.4374 

.90 

.4751 

.7127 

.161  .0178 

.0356 

.0534 

.41 

.0730 

.1461 

.2191 

.66|  .2984 

.4476 

.91 

.4831 

.7246 

.171  .0195 

.0390 

.0585 

.42 

.0757 

.1515 

.2272 

.67 

.3052 

.4578 

.92 

.4911 

.7366 

.18 

.0212 

.0425 

.0637 

.43 

.0785 

.1569 

.2354 

.68 

.3120 

.4681 

.93 

.4991 

.7486 

.19 

.0230 

.0461 

.0691 

.44 

.0812 

.1624 

.2436 

.69 

.3189 

.4784 

.94 

.5072 

.7607 

.20 

.0249 

.0498 

.0747 

.45 

.0840 

.1680 

.2520 

.70 

.3259 

.4889 

.95 

.5153 

.7729 

.21!  .0268 

.0536 

.0803 

.46 

.0868 

.1736 

.2604 

.71 

.33291  .4994 

.96 

.5234 

.7851 

.22 

.0287 

.0574 

.0861 

.47 

.0897 

.1793 

.2690 

.72 

.3400 

.5100 

.97 

.5316 

.7974 

.231  .0307 

.0614 

.0921 

.48 

.0925 

.1851 

.2776 

.73 

.3471 

.52061 

.98 

.5399 

.8098 

.24 

.0327 

.0654 

.0981 

.49 

.0954 

.1909 

.2863 

.74 

.3542  .53141   .99 

.5481 

.8222 

.25'  .0348 

.0696 

.1043 

.50 

.0984 

.1967 

.2951 

.75 

.3614 

.54221  1.00 

.5565 

.8347 

i 

i 

[I 

Unit  of  Measurement. 

The  miner's  inch  was  the  first  common  unit  of  measure- 
ment of  flowing  water  in  nearly  all  of  the  Western  States, 
the  system  or  method  having  been  evolved  by  the  early 
placer  miners  for  the  measurement  of  the  water  to  which 
they  were  entitled.  Though  this  unit  and  method  of  meas- 
urement was  fairly  well  adapted  for  the  use  of  the  miners 
in  the  measurement  of  the  small  streams,  the  unit  is  rather 
indefinite  and  intangible  and  the  method  of  measurement  is 
cumbersome  and  not  adapted  to  the  measurement  of  large 
streams  such  as  are  now  being  used  for  irrigation  purposes. 
The  miner's  inch  was  the  amount  of  water  that  would 


76  REPORT  OF  STATE  ENGINEER. 

flow  through  a  sharp  edged  orifice  one  inch  square  under 
a  given  pressure.  The  pressure  and  consequent  size  of  the 
miner's  inch  varied  in  different  States,  which  resulted  in 
considerable  confusion.  An  Idaho  miner's  inch  is  the 
amount  of  water  that  will  flow  through  a  sharp,  thin  edged 
orifice  one  inch  square  with  a  pressure  of  four  inches  over 
the  center  of  the  opening.  An  Idaho  miner's  inch  happens 
to  equal  txactly  nine  gallons  per  minute. 

Second  Foot. 

A  much  better  unit  and  method  of  measurement,  and 
one  which  is  adapted  to  streams  of  all  sizes  and  descrip- 
tions, has  now  been  evolved.  It  is  definite  and  more  easily 
understood,  but  it  is  hard  to  make  the  old  time  irrigators 
forget  the  old  method  and  adopt  the  newr  one,  and  this  is 
being  only  gradually  accomplished.  The  newer  unit  of 
measurement,  and  the  one  that  is  the  best  that  has  been 
yet  devised  for  the  measurement  of  all  sizes  of  streams 
of  flowing  water,  is  the  cubic  foot  per  second,  which  simply 
represents  what  the  term  itself  signifies,  i.  e.,  a  cubic  foot 
of  water  each  second  of  time,  it  only  being  necessary  to 
determine  the  area  of  the  cross  section  of  a  stream  in 
square  feet  and  the  average  velocity  in  feet  per  second, 
which  two  factors  multiplied  together  give  the  correct  dis- 
charge of  the  stream  in  cubic  feet  per  second.  The  cubic 
foot  per  second  is  now  the  legal  standard  for  the  measure- 
ment of  flowing  water  in  Idaho,  it  having  been  adopted 
by  the  Idaho  Legislature  in  1899.  The  cubic  foot  per 
second  (commonly  known  as  the  "second  foot")  repre- 
sents a  flow  of  water  which  will  exactly  fill  a  vessel  con- 
taining one  cubic  foot  each  second  of  time  for  as  long  a 
period  as  it  is  allowed  to  flow ;  hence  a  flow  of  one  cubic 
foot  per  second  delivers  60  cubic  feet  per  minute,  or  3,600 
cubic  feet  per  hour,  or  86,400  cubic  feet  in  a  day  of  twenty- 
four  hours.  A  flow  of  one  cubic  foot  per  second  equals 
almost  exactly  fifty  Idaho  miner's  inches  or  450  gallons 
per  minute.  One  Idaho  miner's  inch,  therefore,  equals  a 
flow  of  nine  gallons  per  minute. 

Acre  Foot. 

Where  large  volumes  of  water  are  to  be  considered  the 
expression  of  the  amount  in  cubic  feet  would  involve  the 
use  of  such  large  numbers  that  the  same  would  be  cumber- 
some. In  order  to  simplify  these  expressions!  the  term 


REPORT  OF  STATE  ENGINEER.  77 

"acre  foot"  is  used.  An  acre  foot  represents  enough  water 
to  cover  an  acre  one  foot  in  depth,  or  43,500  cubic  feet. 
T|he  use  of  this  term  has  the  additional  advantage  of  being 
easily  compared  with  the  acreage,  as,  for  example1,  a  res- 
ervoir containing  50,000  acre  feet  of  water  would  furnish 
a  depth  of  two  feet  for  25,000  acres  of  land.  A  cubic  foot 
of  water  per  second  flowing  continuously  for  twenty-four 
hours  furnishes  almost  exactly  twienty-four  acre  inches 
or  two  acre  feet  of  water.  Hence  a  continuous  flow 
of  one  cubic  foot  per  second  will  cover  an  acre  one  inch 
deep  in  one  hour,  or  two  inches  in  two  hours,  or  four  acres 
three  inches  deep  in  twelve  hours. 

It  has  been  customary  to  express  the  Duty  on  any  project 
as  a  certain  fraction  or  number  of  miner's  inches  per  acre, 
or  the  nutmber  of  acres  served  by  a  continuous  flow  of 
a  cubic  foot  per  second.  The  expression  of  the  Duty  in 
this  manner,  however,  is  rather  impractical  and  too  indefi- 
nite for  experimental  purposes,  for  the  total  amount  of 
water  applied  depends  not  only  upon  the  size  of  the  stream 
used  per  acre  and  whether  or  not  it  has  flowed  con- 
tinuously, but  upon  the  length  of  the  irrigation  season  as 
well.  In  order  to  eliminate  all  variable  elements  and  make 
all  results  strictly  comparable,  the  amounts  that  have  been 
applied  and  retained  on  the  soil  in  this  investigation  are 
herein  tabulated  as  acre  feet  per  acre,  or  depths  of  appli- 
cation on  the  land,  these  two  expressions!  being  equivalent. 
The  results  have  thus  been  made  strictly  comparable  and 
should  be  easily  understood. 

Hydraulic  Equivalents  Which    Will    Be    Found    Useful     to 

Irrigators. 

In  order  to  throw  additional  light  on  the  various  terms 
used  in  this  report  and  to  allow  ready  comparison  of  the 
different  units,  the  following  hydraulic  equivalents  are 
inserted : 

1.  One  Idaho  miner's  inch  equals  approximately  one- 
fiftieth  of  a  cubic  foot  per  second,  or  9  gallons  per  minute. 

2.  A   cubic   foot   per  second  equals  approximately  50 
Idaho  miner's  inches,  or  450  gallons!  per  minute. 

3.  One  cubic  foot  per  second  for  24  hours  equals  ap- 
proximately 2  acre  feet,  or  one  acre  inch  per  hour. 

4.  One  acre  foot  equals  enough  water  to  cover  an  acre 
exactly  one  foot  in  depth,  or  43,560  cubic  feet. 


78  REPORT  OF  STATE  ENGINEER. 

5.  One  miner's  inch  per  acre  for  100  days  equals  3.97 
feet  deep  on  the  land. 

6.  One  miner's  inch  per  acre  for  150  days  equals  5.95 
feet  deep  on  the  land. 

7.  five-eighths   miner's    inch    per   acre    for   100    days 
equals  2.48  feet  deep  on  the  land. 

8.  Five-eighths  miner's  inch  per  acre    for    150     days 
equals  3.72  feet  deep  on  the  land. 

9.  One-half  miner's  inch  per  acre  for  100  days  equals 
1.98  feet  deep  on  the  land. 

10.  One-half  miner's  inch  per  acre  for  150  days  equals 
2.98  feet  deep  on  the  land. 

Determination  of  Areas  and  Yields. 

The  areas  of  all  experimental  plots  and  tracts  included 
in  the  investigation,  with  the  exception  of  the  areas  con- 
tained in  the  large  projects,  have  been  determined  by  actual 
surveys  with  a  transit  and  chain.  The  surveys  were  care- 
fully plotted  in  the  office  to  a  scale  of  100  feet  to  the  inch, 
the  areas  being  determined  by  the  use  of  a  polar  planimeter. 
It  is  believed  that  the  areas  of  all  experimental  tracts  of 
a  smaller  size  than  160  acres,  as  tabulated  herein,  are  ac- 
curate to  within  one-hundredth  of  an  acre. 

The  yields  produced  have  been  weighed  whenever  pos- 
sible. In  other  cases,  where  the  farms  were  located  at  long 
distances  from  a  set  of  scales,  the  yields  of  hay  have  been 
computed  in  the  stack  by  the  approved  rules  used  in  com- 
mon practice.  The  yields  from  the  different  experimental 
tracts  were  invariably  cut,  threshed  and  stacked  separately, 
extreme  care  being  used  at  all  times  to  avoid  error. 
Though  the  determination  of  the  yields  of  the  hay,  where 
weighing  has  been  impractical,  may  have  been  slightly  in- 
accurate, it  is  certain  that  they  are  comparable,  in  which 
case  the  value  of  the  experiments  have  not  been  vitiated 
in  any  way. 

Soil  Classification. 

A  careful  classification  of  the  soil  from  each  tract  ex- 
perimented upon  to  a  depth  of  at  least  four  feet  has  been 
made  in  the  field  by  means  of  a  sufficient  number  of  test 
pits  in  various  parts  of  each  field  to  determine  with  a  fair 
amount  of  accuracy  the  character  of  the  soil  experimented 
upon.  Chemical  analyses  of  the  soil  have  been  made  in 
but  few  cases.  Typical  samples  of  the  first,  second,  third, 


REPORT  OF  STATE  ENGINEER.  79 

and  fourth  feet  of  the  soil  from  each  tract  experimented 
upon  have  been  secured  and  are  now  filed  away  for  further 
reference.  It  is  regretted  that  the  enforced  brevity  of  this 
report  will  not  permit  of  a  detailed  description  of  the  soil 
of  each  tract,  for  it  has  been  found  that  the  Duty  depends 
upon  the  character  of  the  soil  more  than  upon  any  other 
one  thing. 

Moisture   Determination. 

In  view  of  the  wide  scope  of  territory  included  in  the  in- 
vestigation it  was  deemed  necessary  to  determine  the 
amount  of  moisture  that  existed  in  the  soils  of  the  experi- 
mental tracts  by  reason  of  winter  precipitation,  previous 
irrigation,  seepage,  etc.,  on  or  about  the  time  crops  were 
planted  or  began  their  growth  in  the  spring.  A  careful 
determination  of  the  per  cent  of  moisture  in  the  firne,  sec- 
ond, third  and  fourth  feet  of  soil  of  each  tract  has  there- 
fore been  nuide.  These  determinations  have  been  of 
material  assistance  in  comparing  the  various  results  se- 
cured, for  some  tracts  have  been  found  to  contain  twice 
MS  much  moisture  at  planning  time  as  others.  Except  at 
the  permanent  experiment  stations  conducted  by  the  state 
and  the  government  it  has  been  impossible  on  account  of 
lack  of  time  and  funds  to  make  a  determination  of  the 
moisture  in  the  soils  at  the  end  of  the  irrigation  season,  al- 
though this  would  have  been  very  desirable. 

Reimbursement  of  Loss. 

It  has  been  necessary  in  but  few  cases  to  enter  into  writ- 
ten contracts  with  the  owners  of  the  tracts  experimented 
upon,  for  the  irrigation  farmers  of  Idaho  have  almost  with- 
out exception  been  glad  to  co-operate  in  the  investigation. 
It  has  been  necessary,  however,  to  make  reimbnrsment 
to  the  owners  for  crop  shortage  occasioned  by  the  variation 
of  the  water.  The  yield  made  on  the  tract  handled  by  the 
owner  has  been  used  as  the  basis  for  such  settlements. 
Reimbursement  of  the  owners  has  been  found  necessary 
in  only  about  one-third  of  the  cases  but  had  it  been  possible 
to^  induce  the  owners  of  the  tracts  experimented  upon  to 
reimburse  the  state  in  those  cases  where  the  yield  was  in- 
creased by  reason  of  the  water  variation  there  would  have 
been  no  fund  required  for  reimbursement  of  loss. 
Measurement  of  Use  of  Water  With  Water  Registers. 

The  usual  method  of  procedure  throughout  the  investi- 


80  REPORT  OF  STATE  ENGINEER. 

gation  was  to  detail  one  assistant  to  four  or  five  fifteen- 
acre  tracts  upon  as  many  farms  in  the  same  neighborhood. 
This  assistant  devoted  his  entire  time  and  attention  dur- 
ing the  season  to  the  measurement  of  water  and  the  detail 
work  in  connection  with  the  four  or  five  experimental 
tracts,  each  of  which  was  divided  into  three  approximately 
oqual  parts.  This  method  of  procedure  was  rather  expen- 
sive in  that  one  assistant  could  not  cover  much  territory 
during  the  season.  In  order  to  broaden  the  investigation 
and  determine  the  normal  use  of  water  by  the  farmers  the 
water  applied  to  a  comparatively  large  area  was  measured 
each  season  by  automatic  water  registers,  which  were  in- 
stalled for  the  purpose  on  the  weirs  in  the  head  ditches 
leading  to  the  tracts  in  question.  Each  of  these  water 
registers  would  measure  accurately,  with  but  little  atten- 
tion, the  amount  applied  during  the  season  to  tracts  vary- 
ing in  size  from  fifteen  to  one  hundred  and  fifty  acres. 
The  investigation  has  in  this  way  been  broadened  consid- 
erably over  what  it  would  have  been  had  all  water  been 
measured  by  assistants  employed  for  the  purpose.  The 
water  applied  to  by  far  the  majority  of  the  tracts  included 
in  the  investigation  has  been  measured  by  men  employed 
for  the  purpose,  but  the  area  served  by  the  water  registers 
was  nearly,  if  not  quite,  equal  to  that  measured  by  the 
men  themselves. 

Weather  Conditions. 

It  has  not  been  possible  or  practical  to  install  a  rain 
gauge  in  connection  with  each  experimental  tract  included 
in  the  investigation.  The  Weather  Bureau  of  the  U.  S. 
Department  of  Agriculture  has  numerous  co-operative 
observer  stations  scattered  quite  uniformly  throughout  the 
territory  involved.  The  precipitation  that  has  occurred 
upon  the  experimental  tracts  has  been  assumed  to  be  equal 
to  that  of  the  United  States  Weather  Bureau  Station  near 
est  the  tract  in  question.  While  it  is. known  that  this  may 
vary  a  small  per  cent  from  accuracy,  it  is  considered  that 
the  slight  differences  that  may  have  existed  can  be  safely 
neglected.  Any  peculiarities  of  weather,  such  as  excess 
ive  or  deficient  precipitation,  or  early  or  late  frosts,  have 
been  carefully  noted  and  taken  into  consideration  when 
arriving  at  conclusions  in  regard  to  any  of  the  experi 
ments. 

The  growing  season  of  1910  in  Idaho  was  the  dryest  on 


REPORT  OF  STATE  ENGINEER. 

record.  The  precipitation  during  seven  consecutive 
months  from  March  to  September  inclusive  was  below  nor- 
mal. The  temperature  ranged  above  normal  during  al- 
most the  entire  season.  The  seasons  of  1911  and  1912 
were  quite  similar  to  one  another  and  averaged  much 
cooler  than  that  of  1910.  The  precipitation  during  both 
1911  and  1912,  however,  ranged  above  normal  during  the 
growing  season,  as  may  be  seen  from  the  tables  which  fol- 
low. 

The  season  of  1913  was  another  with  high  precipitation, 
the  precipitation  averaging  above  normal  for  the  six  grow- 
ing months  at  Boise,  Buhl,  Hollister,  Idaho  Falls,  Oakley 
and  Twin  Falls,  Gooding  being  the  only  place  under  in- 
vestigation where  the  precipitation  was  below  normal.  The 
temperature  during  the  season  of  1913  was  a  fair  average 
of  that  of  the  other  three  years,  1910  to  1912  inclusive, 
with  the  exception  that  the  fourth  week  of  August  instead 
of  the  third  week  of  July  was  the  hottest  week  of  the  year, 
the  third  week  in  July  having  been  the  hottest  week  for 
three  consecutive  years  at  all  of  the  places  included  in  the 
investigations.  June  of  1913,  at  all  stations,  was  a  very 
cool  month,  an  unusual  amount  of  precipitation  having 
fallen  during  the  month. 

Considering  the  weather  conditions  during  the  four 
years  as  a  whole,  as  one  can  do  with  considerable  detail 
from  the  following  charts  and  tables,  it  would  seem  that 
the  investigation  covered  enough  different  years  with  their 
varied  climatic  conditions  to  insure  accuracy  and  fairness 
in  the  average  results -that  have  been  obtained. 

The  following  tables  and  charts  have  been  compiled  from 
the  records  of  the  United  States  Weather  Bureau  for  the 
purpose  of  showing  in  condensed  form  the  weather  condi- 
tions that  existed  during  the  four  years  covered  by  the  in- 
vestigation. The  temperature  chart  giving  the  range  of 
temperature  during  the  four  growing  seasons  has  been 
made  to  include  only  Boise  and  Twin  Falls.  These  two 
points  are  quite  widely  separated,  but  both  are  in  the  midst 
of  large  irrigated  areas  in  which  rather  complete  investi- 
gations have  been  made  and  a  fair  idea  of  the  temperature 
range  may  be  gained  from  them. 


82 


REPORT  OF   STATE   ENGINEER. 


Precipitation  in  Inches. 


Local  ity 

Length  of 
record  —  years 

Averag-e 
precipita  n 

Monthly  Precipitation 

Total  for  six 
months 

Per  cent  of 
normal 

"rt 

3 

B 

C 

«u 

£2 

It* 
*** 

1 

<< 

K 
n 
% 

V 

c 
s 
l-t 

"5 

i-> 

oc 

5 

bj 

3 
< 

a 
& 

Seasonof  1910 
Blackfoot 

14 
25 
3 
5 
1 

10.46 
12.71 
12.22 
10.54 

4.66 
4.10 
5.13 
3.51 

0.67 
1.10 

0.82 
1.05 
0.77 
0.81 
0.06 
0.33 
0.73 

1.59 
0.86 
1.03 
1.15 
1.67 
0.95 
0.15 
0.43 
1.35 

3.34 
.92 
.96 
.96 
.94 
.68 
.38 

0.95 
0.62 
0.47 
0.89 
iO.35 
0.15 

'  "6.'53 

0.78 
1.14 
0.55 
0.84 
0.32 
0.80 
0.75 
0.43 
0.52 

2.57 
1.97 
1.13 
1.77 
2.91 
2.29 
1.75 
1.74 
2.00 

1.94 
0.43 
2.05 
1.33 
1.36 
0.63 
0.57 

0.58 
1.58 
0.15 
1.79 
2.39 
1.36 
1.25 
0.75 

0.10 
0.30 
0.25 
0.03 
0.08 
0.06 
0.14 
0.01 
0.06 

2.55 
2.34 
1.44 
1.06 
1.53 
2.67 
2.76 
0.83 
1.95 

0.86 
0.90 
1.77 
0.67 
0.89 
0.46 
0.86 

1.64 
2.49 
0.91 
2.40 
2.99 
3.01 
4.32 
2.54 

0.21 
T 
0.28 
T 
0.24 
0.27 

o.n 

0.18 
0.12 

0.05 
0.18 
0.23 
0 
0.04 
0.30 
0.84 
0.05 
T 

1.27 

0.18 
1.22 
0.33 
1.60 
0.48 
0.04 

2.01 
2.29 
0.73 
.65 
.86 
.85 
.29 
.50 

T 
0 
0 
0 
0 
0 
T 
0 

? 
T 

j 

0.07 
0 
0.04 
0 

0.07 
0.08 
0.21 
T 
'  2.28 
0.16 
T 
' 

0.03 
0.13 
0.08 
0.13 
0.08 
0.84 
1.17 
0.17 

0.47 

0.50 

2.23 
3.04 

48 
74 

Boise    

Buhl 

Caldwell      

0.89 
0.44 
1.33 
1.30 
0.54 
0.95 

0.04 
T 
0.12 
T 

0.03 
10.67 
0.30 
0.10 
T 

0.77 
0.30 
0.53 
0.18 
0.44 
0.30 
0.31 

0.65 
0.05 
0.05 
0.49 
0.88 
0.65 

"2.'09 

2.81 
1.85 
3.27 
2.36 
1.49 
2.38 

6.80 
5.35 
3.95 
S.98 

6.18 
6.95 
5.80 
3.19 
5.30 

8.25 
3.81 
7.74 
3.47 
8.51 
3.71 
3.16 

5.86 
7.16 
2.39 
7.35 

8.55 
7.86 

"i.'ss 

80 

'"81 
39 
51 
54 

166 
103 
110 
124 
144 
115 
124 
76 
134 

201 
76 
18, 
107 
137 
90 
83 

14H 
13fi 
7? 
109 
13* 

..^. 

167 

Gooding 

Hailey  

8 
15 
3 
5 

26 
4 
6 
2 
9 
16 
18 
6 
3 

27 
5 
7 
3 
17 
7 
4 

28 
7 
4 
2 
18 
19 

8 

17.15 
14.44 
15.06 
12.90 

12.71 
11.15 
10.31 
9.40 
16.27 
14.00 
9.58 
12.10 
13.86 

12.71 
10.90 
10.05 
10.82 
14.23 
11.98 
13.76 

12.71 
11.25 
11.14 
12.97 
14.35 
9.99 

'ii.'is 

4.04 
6.00 
2.91 
4.40 

4.10 
5.17 
3.59 
3.20 
4.30 
6.06 
4.68 
4.19 
3.96 

4.10 
4.99 
4.13 
3.24 
6.19 
4.13 
3.82 

4.10 
5.25 
3.04 
6.74 
6.32 
5.04 

4.54 

Idaho  Falls  

Twin  Falls 

Season  of  1911 
Boise 

Buhl  

Caldwell 

Gooding  

Hailey             

Idaho  Falls  
Oakley    

Twin  Falls  
Wendell    

Season  of  1912 
Boise  

Buhl 

Caldwell  

Gooding  
Idaho  Falls  
Twin  Falls 

Wendell  

Season  of  1913 
Boise  
Buhl  

Gooding  
Hollister  

Idaho  Falls  
Oakley 

Rogerson  
Twin  Falls  

84  REPORT   OF   STATE   ENGINEER. 

Method  of  Interpreting  Results. 

The  correct  and  proper  analysis  of  the  results  that  have 
been  secured  has  been  the  most  difficult  part  of  the  en- 
tire investigation.  There  are  so  many  factors  other  than 
mere  amount  of  water  application  that  might  influence 
the  yields  that  have  been  secured  from  the  experimental 
tracts  that  the  proper  interpretation  of  the  results  has 
indeed  been  a  difficult  problem.  It  has  been  plain  that 
under  normal  conditions  the  tract  producing  the  best  yield 
has  had  the  best  application  of  water  for  the  soil  and  crop 
in  question.  In  some  cases,  however,  the  largest  yield  has 
exceeded  the  yield  of  one  of  the  other  two  tracts  by  less 
than  5  per  cent,  yet  the  amount  of  water  applied  might  have 
exceeded  that  applied  to  the  second  tract  by  as  much  as 
100  per  cent.  In  such  cases  it  has  been  plain  if  economy 
of  time  and  water  are  to  be  considered  that  the  tract 
making  the  smaller  yield  was  handled  more  economically. 

The  investigation  as  a  whole  has  made  it  plain  that  a 
single  experiment  is  not  dependable,  because  of  the  in- 
sidious1 variations  that  sometimes  unavoidably  creep  in. 
There  have  sometimes  been  great  variations  in  the  yields 
produced  by  the  same  amount  of  water  on  the  same  crop 
upon  adjoining  farms  during  the  same  season.  It  became 
evident  beyond  contradiction  early  in  the  investigation  that 
the  results  secured  from  a  large  number  of  tracts  con- 
sisting of  a  considerable  area  were  the  only  data  that 
would  be  found  dependable;  also  that  an  average  of  the 
data  secured  during  as  many  years  as  possible  was  the 
most  dependable  for  in  no  other  way  could  the  peculiarities 
of  the  individual  tracts  or  the  seasonal  variations  in  the 
climate  be  neutralized. 

It  was  found  early  in  the  investigation  that  the  various 
crops  naturally  formed  themselves  into  two  groups:  (1) 
those  requiring  the  least  water;  and  (2)  those  requiring 
the  most  water.  The  grains,  both  spring  and  winter, 
potatoes,  and  clean  cultivated  orchards  were  found  to  lie 
in  group  No.  1,  while  alfalfa,  the  clovers  and  pasture  were 
found  to  lie  in  group  No.  2,  the  crops  in  the  second  group 
requiring  nearly  twice  as  much  water  as  the  crops  in  group 
No.  1.  The  following  tables  have  been  compiled  and  give 
in  a  condensed  form  a  brief  resume  of  the  experiments 
that  have  been  conducted.  The  crops  are  grouped  in  the 
tables  according  to  their  water  requirements  into  groups 
No.  1  and  No.  2.  It  is  to  be  regretted  that  the  enforced 


KEPOBT  OF  STATE  ENGINEER.  85 

brevity  of  this  report  will  not  permit  of  even  a  brief  de- 
tailed description  of  each  experiment,  the  space  allotted  to 
each  experiment  in  the  tables  which  follow  being  the  only 
detailed  description  of  each  experiment  that  can  be  in- 
cluded. These  tables  show,  (1)  the  kind  of  crop,  (2)  the 
altitude,  (3)  a  brief  description  of  the  class  of  soil,  (4) 
the  area  of  each  tract  experimented  upon,  (5)  the  precipi- 
tation recorded  at  the  nearest  Weather  Bureau  Station, 
(6)  the  date  of  the  first  irrigation  during  the  season,  (7) 
the  length  of  the  irrigation  season  in  days,  (8)  the  number 
of  irrigations  that  were  applied  during  the  season,  (9) 
the  total  depth  of  irrigation  water  that  was  applied  and 
retained  upon  the  tract  in  question,  all  waste  water  hav- 
ing been  deducted,  unless  otherwise  specified,  and  (10) 
the  yields  that  were  secured  per  acre.  For  convenience 
the  results  from  the  three  or  more  plots  on  each  farm 
are  grouped  together,  the  experiments  on  the  different 
farms  being  separated  slightly  in  the  tables.  The  readers 
are  requested  to  bear  in  mind  that  the  "total  depth  ap- 
plied" includes  only  the  irrigation  water  that  was  retained 
upon  the  tract  in  question,  the  rainfall  during  the  season 
being  given  in  another  column. 


86 


REPORT  OF  STATE  ENGINEER. 


Table  Showing-  Effects  of  Using-  Different  Amounts  of  Water  on  Grains. 
Alfalfa,  Etc.,  in  Idaho,  During  the  Seasons  of  1910-11-12-13. 


Kind  of  crop 


Grain-1910 
lOats   

2  Oats   

3  Oats    . 


Wheat 
5  Wheat 
(>  Wheat 

Wheat 

8  Wheat 

9  Wheat 


10|Oats 


Wheat 
Wheat 


13  Wheat 

14|Wheat 
15|Wheat 
16  Wheat 

17 (Oats  ... 
!8|Oats  ... 
!9|Oats  ... 

20jOats  ... 
2l(Oats  ... 
22|Oats  ... 


23  Wheat  

24  Wheat  

25  Wheat  


Oats 

Oats 

28  Oats 


29  Wheat 

30  Wheat ., 

31  Wheat 

32|Oats 

33|Oats 

34  Oats 


35  Wheat... 

36  Wheat 

371  Wheat , 

38|Oats 

39|0ats 

40!Oats 


41 1  Wheat.. 
42!  Wheat. . 
431  Wheat.. 
44 1  Wheat., 
45|  Wheat.. 
50  Wheat.. 
51!  Wheat., 

I 

521  Wheat., 
531  Wheat., 
54 1  Wheat. 


Class  of  soil 


3968  Slightly  Sandy  Loam. 
3968  Slightly  Sandy  Loam. 
3968  Slightly  Sandy  Loam. 

3800  Medium  Clay  Loam 

^800|Medium  Clay  Loam.... 
:5800|Medium  Clay  Loam 

4949 1  Very    Gravelly... 

4949| Very    Gravelly 

Gravelly 


4949 1  Very 
1949;  Very 


4949 


Gravelly. 


Very 


Gravelly 

4949  Very    Gravelly 

-1949  Very    Gravelly 

4949  Gravelly  Clay , 

1949  Gravelly   Clay 

4949  Gravelly   Clay 

1699  Very  Gravelly 

4699  Very  Gravelly 

4699|Very  Gravelly 

47 421  Impervious  Clay  Loam. 
4742! Impervious  Clay  Loam. 
4742| Impervious  Clay  Loam. 


4497  Very  Sandy. 
4497  Very  Sandy. 
4497 1 Very  Sandy. 


2482  Impervious  Clay  Loam. 
2482  Impervious  Clay  Loam. 
2482  Impervious  Clay  Loam. 

2607  Uniform    Clay  Loam... 

2607  Uniform    Clay  Loam . . . 

2607|Uniform    Clay  Loam... 

I 

2460| Coarse    Sandy  Loam. 

2460  Coarse    Sandy  Loam. 

2460  Coarse    Sandy  Loam. 

3800 1  Uniform  Clay  Loam. 
3800IUniform  Clay  Loam. 
3800'Uniform  Clay  Loam. 

24821  Impervious  Clay  Loam 
24821  Impervious  Clay  Loam 
2482!Impervious  Clay  Loam 


3572 1  Medium 
3572 1  Medium 
3572|Medium 
3572  Medium 
35  riMcUum, 
?572 1  Medium 
,'572 1  Medium 

I 

3572  (Medium 
3572 1  Medium 
3572' Medium 


Clay  Loam. 
Clay  Loam. 
Clay  Loam. 
Clay  T.'Oam. 
Clay  Loan- 
Clay  Loam. 
Clay  Loam . 

Clay  Loam . 
Clay  Loam . 
Clay  Loam. 


2.90|  5-27 

3.041  5-21 

3.04|  5-20 

3.04!  5-19 


605.1  Ibs 
1227.3  Ibs 
1238.6  Ibs 


RKPORT  OF  STATE  ENGINEER. 


87 


Table  Showing  Effects  of  Using-  Different  Amounts  of  Water  on  Grains, 
Alfalfa,  Etc.,  in  Idaho,  During-  the  Seasons  of  1910-11-12-13.— Continued. 


Kind  of  crop 


Grain— 1910 

Continued1 

55 1  Wheat 

jtijWheat 

o7|  Wheat 

uSi  Wheat 

591  Wheat 

uO|Wheat 

61|  Wheat 

62|  Wheat 

t>3.  Wheat 

64  (Wheat 

05  Wheat 

66|Barley 

t>7|Barley 

tiSI  Barley   


69|Oats 

iGOats 

71  Oats 

72|  Wheat 

73  Wheat 

74  Wheat 


Wheat.. 
76  Wheat.., 


77 


78  Potatoes 

79  Potatoes 

80  Potatoes 


Wheat. 


81  Oats 

82  Oats 

Oats 

Alfalfa,  Etc. 

1910 
1  Alfalfa... 


2  Alfalfa 

3  Alfalfa. 

4  Alfalfa. 

5  Alfalfa. 


6  Red   Clover. 

7  Red  Clover, 
si  Red  Clover. 

91  Alfalfa... 

101  Alfalfa 

11!  Alfalfa 

121  Alfalfa 

13|  Alfalfa 

14|  Alfalfa 

15|  Alfalfa... 

16!  Alfalfa 

17!  Alfalfa 

I 
18|  Alfalfa 


3572 1  Medium 
3572  i  Medium 
3572  j  Medium 

3572 1  Medium 

3572|Medium 
3572 1  Medium 
3572  Medium 
3572|Medium 
2|Medium 
3572 1  Medium 
J572J  Medium 

3572|Medium 
3572 1  Medium 
3572jMedium 


3572 1  Medium 
55721  Medium 
5572 1  Medium 

I 

5572 1  Medium 
5572 1  Medium 
35721  Medium 

3572|Medium 
;572|Medium 
]572|Medium 

3572|  Medium 
5572 1  Medium 
35,2|Medium 


3572 


3572 

3572  Medium 


I 


44971  Very 
4497|Very 
4497!  Very 


2367|Impervious   Clay   Loam 


lass  of  soil 

1 

Area 
—  acres 

SI 

it 

Date  of  first 
irrigation 

Ir.  season—  days 

rt 

"o 
0 

'Total  depth  irri- 
gation water 
L-  applied—  feet 

1 

Clay    Loam  . 

.086 

1.85 

5-20 

43 

4 

.945 

143 

Clay    Loam..... 

.089 

1.85 

5-20 

54 

5 

1.100 

193 

Clay    Loam...., 

.074 

1.85 

5-20 

Gl 

6 

1.601 

20C 

Clay    Loam  

.089 

1.85 

5-21 

GO 

9 

2.355 

21C 

Clay    Loam  — 

.176 

1.85 

0 

.000 

52 

Clay    Loam  

.088 

1.85 

*5-20 

'a 

2 

.434 

122 

Clay    Loam  — 

.089 

1.85 

5-20 

43 

9 

.594 

135 

Clay  Loam  

.091 

1.85 

5-20 

43 

4 

.907 

182 

Clay    Loam  — 

.088 

1.85 

5-20 

54 

5 

1.091 

210 

Clay    Loam  — 

.093 

1.85 

5-21 

GO 

1.786 

225 

Clay    Loam  — 

.074 

1.85 

5-21 

GO 

y 

3.010 

263 

Clay    Loam  — 

.962 

1.85 

5-17 

32 

3 

1.032 

15C 

Clay    Loam  — 

.963 

1.85 

5-17 

58 

4 

1.312     17S 

Clay    Loam  — 

.968 

1.85 

5-18 

G8 

5 

1.879     202 

Clay    Loam  

.959 

1.85 

5-24 

23 

2 

.560     144 

Clay    Loam  — 

.957 

1.85 

5-25 

41 

3 

1.097     184 

Clay    Loam  

.962 

1.85 

5-23 

51 

4 

1.450     204 

Clay    Loam  563 

1.85 

5-26 

22 

2 

.780     117 

Clay    Loam  — 

.591 

1.85 

5-26 

4U 

3 

1.269     153 

Clay    Loam  — 

.769 

1.85 

5-26 

GO 

4 

1.841     158 

Clay    Loam  

.959 

1.85 

5-9 

23 

2 

.808     137 

Clay    Loam  — 

.964 

1.85 

5-9 

42 

3 

1.101     121 

Clay    Loam  

.968 

1.85 

5-9 

51 

4 

1.327     174 

Clay    Loam  — 

.641 

1.85 

5-13 

68 

3 

.876 

630 

Clay    Loam  — 

.652 

1.85 

5-13 

88 

5 

1.496 

1193 

Clay    Loam  — 

.636 

1.85 

5-13 

97 

6 

2.046 

1293 

Clay    Loam  — 

5.70 

1.85 

5-12 

64 

3 

1.401         4 

Clay    Loam  — 

4.48 

1.85 

5-17 

60 

4 

1.766         5 

Clay    Loam  — 

1.98 

1.85 

5-19 

59 

4 

2.486         7 

Clay  Loam  ;        .983 

1.85 

5-8 

88 

G 

4.49 

Clay  Loam  \      5.75 

1.85 

5-7 

43 

2 

1.306 

Clay  Loam  

3.72 

1.85 

5-9 

79 

8 

1.872 

Clay   Loam  

3.56 

1.85 

5-10 

78 

3 

2.104 

ravelly  

10.65 

2.36 

5-27 

88 

g 

11.20 

ravelly  

3.31 

2.36 

5-6 

113 

7 

6.92 

ravellv 

4.32 

2.36J  K-7 

L17    9 

8.40 

ravelly  

3.98 

2.36 

5-4 

L14|10 

12.98 

ravellv  

2.33 

2.36 

5-3 

101 

4 

6.352 

ravelly 

6.77 

2  36 

5-2 

105 

6 

6  925 

ravelly  

2.51 

2.36 

4-27 

110 

7 

9.401 

Clay   Loam.... 

3.20 

2.36 

5-6 

104 

4 

1.409 

Clav    Loam  — 

3.16 

2.36 

5-6 

102 

6 

1.953 

Clay   Loam.... 

3.37 

2.36 

5-6 

103 

6 

2.221 

indv                       » 

3.38 

2  23 

5-27 

86 

n 

7   KM 

indv              

4.15 

2.23 

5-27 

50 

5|  2.649 

vndv.  .. 

4.29 

2.23 

5-27 

59 

71  4.825 

2.81    |  2.81|  3-29|144(  8(  1.895 


Yield 
per  acre 


Ibs 
Ibs 
Ibs 

Ibs 

Ibs 
Ibs 
Ibs 
Ibs 
Ibs 
Ibs 
Ibs 

1509.4    Ibs 
Ibs 
2026.9    Ibs 

L2  Ibs 
1.5  Ibs 
f.8.  Ibs 

1.4  Ibs 
1.8  Ibs 
L.3  Ibs 

1.4  Ibs 
..6    Ibs 
!.8    Ibs 

!.6    Ibs 

1.5  Ibs 
!.3    Ibs 

43.3    bu 

54.6  bu 

73.7  bu 


8.7    tons 

3.30  ton? 

3.56  tons 
4.74  tons 

4.2    tons 

3.78  tons 
4.85  tons 
4.60  tons 

3.78  tons 
3.65  tons 
5.20  tons 

5.04  tons 
3.41  tons 
5.72  tons 

4.44  tons 
4.28  tons 

4.57  tons 

4.00  tons 


88 


REPORT  OP  STATE  ENGINEER. 


Table  Showing  Effects  of  Using  Different  Amounts  of  Water  on  Grains, 
Alfalfa,  Etc.,  in  Idaho,  During  the  Seasons  of  1910-11-12-13.— Continued. 


Number 

Kind  of  crop 

Altitude 

Class  of  soil 

Area 
—  acres 

Is 

Bd 

s& 
<j  ~ 

V  Z 

^a 
£« 

•Date  of  first 
irrigation 

Ir  season  —  days 

•j. 

B 

re 
bi 

'u 
X. 

Total  depth  irri- 
gation water 
applied  —  feet 

Yield 
per  acre 

i 

% 
«| 

22 
2o 

21 
25 

1 

27; 

J 

29 

30 
31 
32 

1 
2 
3 

4 
5 

6 

7 
8 
9 

10 

11 
12 

13 
14 
15 

16 

17 

1!> 
19 

20 

21 
22 
23 

24 
25 
26 

27 
28 

Alfalfa,  Etc. 
1910-  Cont. 
Alfalfa  

2367 
2367 

2482 
21S2 
2482 

•'607 

[Impervious   Clay   Loam 
[Impervious   Clay   Loam 

Impervious    Clay    Loam 
Impervious    Clay    Loam 
Impervious    Clay    Loam 

Uniform    Clay    Loam  — 
Very    Gravelly  
Very    Gravelly         

3.69 

2.84 

6.32 
6.23 
6.21 

5.08 
158.4 
15.2 
51.0 

2.81 
2.81 

3.00 
3.00 
3.00 

2.80 
3.27 
3.27 
1.85 

3-27 
3-28 

5-7 
5-5 
5-5 

4-28 


143 
114 

115 
120 
99 

in'j 
120 

m 

140 

8 

'J 

7 
7 

6 

.. 

2.848          3.66  tons 
3.457          4.37  tons 

1.434          2.85  tons 
2.112          4.93  tons 
2.251          4.35  tons 

2.821          5.15  tons 
21.13     3  to  3.5  tons 
16.00     3  to  4  tons 
4.80            4       tons 
4.06           4       tons 
4.00           4       tons 

2.34            6.86  tons 
4.05           7.04  tons 
4.72            7.96  tons 

.453         29!5    bu 
1.144         46.9    bu 
1.889        50.8    bu 

.864         30.6    bu 
1.623         33.8    bu 
2.153        38.0    bu 

.635         63.2    bu 
1.123         53.4    bu 
1.808        64.0    bu 

1.161        64.3    bu 
1.414         51.9    bu 
1.442         65.3    bu 

.302        56.6    bu 
1.167        63.2    bu 
2.266         68.9    bu 

.268     * 
.729        11.6    bu 

.656         23.3    bu 
.888         26.0    bu 
1.047        35.0    bu 

.613       112.8    bu 
.955       108.1    bu 
1.062       128.1    bu 

.641         76.5    bu 
1.316         73.5    bu 
1.654  I      72.4    bu 

1.377         20.9    bu 
5.342  |      30.0    bu 

Alfalfa  
Alfalfa       .    .  . 

Alfalfa  

Alfalfa  
Alfalfa  

Alfalfa         .... 

5820 
5330 
3572 
3572 
3572 

3SOO 
3sOO 
3800 

3968 
3968 
3968 

3800 
3800 
3800 

3750 
3750 
3750 

3750 
3750 
3750 

3825 
3825 
3825 

3825 
3700 

3700 
3700 
3700 

3700 

3700 
3700 

4100 
4100 
4100 

4949 
4949 
No 

Alfalfa      

Alfalfa  

Alfalfa  
Alfalfa  and 
Wheat  

Alfalfa  
Alfalfa 

Clay   Loam      

Uniform  Clay  Loam  
Uniform  Clay  Loam  

Medium    Clay   Loam  
Medium    Clay   Loam  
Medium   Clay   Loam  

Uniform  Sandy  Loam... 
Uniform  Sandy  L<o;inu  .. 
Uniform  Sandy  Loam 

Shallow  Clay  Loam  
Shallow  Clay   Loam  
Shallow  Clay  Loam  

Medium  Clay   Loam  — 
Medium  Clay   Loam  — 
Medium  Clay   Loam  — 

Medium  Clay   Loam  — 
Medium  Clay   Loam  — 
Medium  Clay   Loam  — 

Medium  Clay  Loam  
Medium  Clay  Loam  
Medium  Clay  Loam  

Medium  Clay  Loam  
Very  Sandy  Loam  
Very  Sandy  Loam  

31.8 
69.6 

2.92 

2.89 
3.38 

3.56 
3.66 
4.15 

4.24 
4.73 
3.25 

3.59 

7.49 
5.42 

5.80 
4.82 
7.02 

4.01 
6.10 
4.03 

4.580 
6.89 

4.29 
4.01 
4.17 

2.89 
2.90 
3.27 

4.98 
5.11 

1.85 
1.85 

3.04 
3.04 
3.04 

6.18 
6.18 
6.18 

5.35 
5.35 
5.35 

5.50 
5.50 
5.50 

5.50 
5.50 
5.50 

3.19 
3.19 
3.19 

3.19 
5.30 

5.30 
5.30 
5.30 

5.30 
5.30 
5.30 

5.80 
5.80 

5-4 
5-5 

5-7 

7-12 
6-21 
6-17 

6-11 
6-7 
6-5 

6-24 
6-17 
6-14 

6-2 
6-1 
5-29 

6-28 
6-20 
6-8 

7-6 
5-12 

6-8 
6-6 
6-1 

7-12 
6-19 
6-22 

6-25 
6-22 

140 
140 

105 
107 
109 

'2(J 

42 

15 
43 
51 

19 

32 
27 

52 

47 
64 

'35 

53 

45 
43 
54 

40 

4fi 
50 

4 
4 
4 

1 

i 

2 
3 

4 

2 
2 
2 

3 
4 

1 
2 
3 

1 
1 

3 
3 
4 

3 
3 
4 

1 
1 

I 

Alfalf  a 

Grain-1911 
Oats    

Oats 

Oats         

Wheat  

Wheat 

Wheat  

Wheat    

Wheat 

Wheat      

Oats         

Oats 

Oats            .... 

Oats         

Oats 

Oats         

Orchard    .... 

Fall  Rye  
Oats  

Oats 

Very  Sandy  Loam  
Very  Sandy  Loam  

Oats  

Potatoes  

Extremely  Sandy  

Potatoes  
Potatoes  

Oats  

Extremely  Sandy 

Extremely  Sandy  

Deep  Clay  Loam  
Deep  Clay  Loam    

Oats  

Oats 

Deep  Clay  Loam 

4.42 
15.51 
14.91 

5.80 
6.95 
6.95 

6-15 
7-3 
6-16 

49 
53 

Wheat  
Wheat  

Very  Gravelly        .  .      .  . 

Shallow  Sandy  Loam  — 
crop. 

*4  years  old. 

REPORT  OF  STATE  ENGINEER. 


89 


Table  Showing  Effects  of  Using-  Different  Amounts  of  Water  on  Grains, 
Alfalfa,  Etc.,  in  Idaho,  During  the  Seasons  of  1910-11-12-13.— Continued. 


Number 

Kindjof  crop 

Altitude 

Class  of  soil 

i      i 

'    i      ! 

Area 
—  acree 

.2  s 
15« 

Date  of  first 
irrigation 

Ir.  season  —  dajs 

no.  ol  irngat'ns 

Total  depth  irri- 
gation water 
applied  —  feet 

Yield 
per  acre 

29 
30 

:;i 
32 
33 

36 
36 

37 
38 
39 

. 

41 

42 

43 

44 
46 

46 

47 
48 

49 
50 
51 

52 

53 
54 

55 
56 

57 
58 
59 

60 

ill 
62 

63 
64 

66 

66 
67 

68 

69 

7i 

71 

Orain-1911 

Continued 
Potatoes  

Wheat  
Oats  

4949 
4949 

4949 
4949 
4949 

2600 
2000 
2600 

2600 
2600 
2600 

2600 
2600 
2600 

2600 

2000 
2000 

2607 
2607 
2607 

2460 

2460 
2460 

2607 

2607 
2607 

2460 
2460 

2547 
2.147 
2547 

2400 
2400 
2400 

5330 
f,330 
5330 

2460 
2547 
|2641 
2641 
5330 

Sandy  Loam  t 

7.11 

9.83 

3.85 

2.55 
2.96 

8.47 
11.05 
8.64 

2.05 
1.19 
1.65 

3.06 
2.08 
2.60 

5.38 

7.29 
6.25 

6.95 
6.95 

6.95 
6.95 
6.95 

4.09 
4.09 
4.09 

4.09 
4.09 
4.09 

4.09 
4.09 
4.09 

4.09 
4.09 
4.09 

7-20 
6-20 

7-16 
6-30 
6-28 

6-1 
6-7 
6-5 

6-25 
6-26 
6-25 

6-24 
6-23 
6-24 

5-30 
5-24 
6-3 

40 
42 

30 
54 
53 

39 

19 
15 

22 

IS 
21 

2: 

4 
3 

4 

2 
] 

2 

I 

1 
1 
1 

2 
2 
2 

2 
3 
3 

2 

3 
2 

2 
2 

3 

2 
3 

2 
3 
3 

2 
2 
3 

2.828 
3.466 

4.511 
5.943 
10.366 

.307 
.315 

.589 

.263 
.271 
.497 

.294 
.372 
.417 

.185 

.199 
.243 

.557 
.618 
.769 

.461 
.698 
1.076 

1.193 

1.371 
1.428 

.770 
1.367 

1.258 
1.315 
3.095 

.866 
1.186 
1.253 

3.187 
4.280 
6.304 

4.25 
5.26 
3.56 
2.32 
9.484 

.525 

211.8    bu 
31.6    bu 

31.8    bu 
68.4    bu 
57.2    bu 

19.7    bu 
16.0    bu 
22.0    bu 

12.0    bu 
5.0    bu 
5.0    bu 

22.0    bu 
26.0    bu 
26.0    bu 

16.0    bu 
10.6    bu 
17.7    bu 

28.0    bu 
34.8    bu 
31.4    bu 

43.0    bu 
63.0    bu 
73.0    bu 

49.0    bu 

35.5    bu 
37.6    bu 

45.4    bu 
49.5    bu 

47.3    bu 
59.3    bu 
54.1    bu 

27.8    bu 
43.96  bu 
33.59  bu 

45.6    bu 
39.9    bu 
40.9    bu 

* 
* 
* 
* 

3.0  T.   Alf.   & 
30  Bu  Oats 

11.0    bu 

Shallow  Sandy  Loam... 
Sandy  Loam 

Oats  
Oats  

Sandy  Loam  

Sandy  Loam  , 

Wheat  
Wheat  
Wheat  

Wheat  
Wheat  
Wheat  

Oats 

Impervious  Clay  Loam.. 
Impervious  Clay  Loam.. 
Impervious  Clay  Loam.. 

Impervious  Clay  Loam.. 
Impervious  Clay  Loam.. 
Impervious  Clay  Loam.. 

Impervious  Clay  Loam.. 
Impervious  Clay  Loam.. 
Impervious  Clay  Loam.. 

Sandy  Loam  . 

Oats  
Oats 

Oats  

Oats  
Oats  

Sandy  Loam  
Sandy  Loam 

Oats 

Impervious  Clay  Loam. 
Impervious  Clay  Loam. 
Impervious  Clay  Loam.. 

Clay  Loam 

4.56 
1.35 
3.69 

2.58 
2.30 
2.37 

2.56 

6.17 
5.79 

4.40 
5.55 

6.72 
4.16 
5.67 

3.74 
6.21 
4.14 

4.03 

8.63 
5.55 

35.00 
13.15 
31.85 
39.72 
35  59 

6.80 
6.80 
6.80 

6.80 
6.80 
6.80 

6.80 

6.80 
6.80 

6.80 
6.80 

6.80 
6.80 
6.80 

6.80 
6.80 
6.80 

6.18 
6.18 
6.18 

6.80 
6.80 
6.80 
6.80 
6  18 

6-12 
6-12 
6-13 

6-2 

6-4 
6-3 

6-8 

6-8 
6-8 

6-27 
6-25 

6-12 
6-7 
6-5 

6-9 
6-9 
6-10 

7-15 
7-12 
6-23 


6-13 

26 

25 
24 

2S 
K 
3! 

38 

23 

19 

1!) 

35 
32 

32 

33 
34 

34 

18 

20 
38 

122 
122 
122 
122 
71 

Oats  

Oats 

Oats  

Oats  

Clay  Loam 

Oats  
Wheat  

Clay  Loam 

Sandy  Loam 

Wheat... 

Sandy  Loam  .... 

Wheat  

Wheat    . 

Sandy  Loam  Mixed 
With   Clay        

Wheat  - 

Oats  

Sandy  Loam 

Oats            .  .. 

Oats  

1  Sandy  Loam  

Wheat  
Wheat 

Coarse  Sandy  Loam  
Coarse  Sandy  Loam  
Coarse  Sandy  Loam  

Very  Gravelly 

Wheat  

Oats  

Oats            

Oats  

Very  Gravelly 

Orchard 

Clay  Loam  
Coarse  Sandy  Loam  
Clay  Loam  
Clay  Loam  
Very  Gravelly  . 

Orchard 

Orchard 

Orchard  
IGrain    &    Al- 
falfa       

lOats  : 

?600 

Imnervlous  Clav  Loam. 

2.02 

4  09 

5-11 

04 

4 

"Yield  not  measured. 


90 


REPORT  OF  STATE  ENGINEER. 


Table  Showing  Effects  of  Using-  Different  Amounts  of  Water  on  Grains, 
Alfalfa,  Etc.,  in  Idaho,  During  the  Seasons  of  1910-11-12-13. — Continued. 


Kind  of  crop 


Grain  1911 
Continued 

72  Oats 

Oats 


74jCorn 

75|Corn 

76  Corn 


77 1  Wheat. 
78|Wheat. 
79  Wheat. 
SO  Wheat. 
8l|Wheat. 
82 1  Wheat. 
83|Wheat. 

I 

84|Wheat. 
85|Wheat. 
86 1  Wheat. 
87 1  Wheat. 
S8|Wheat. 
89|  Wheat, 
yoi  Wheat. 


91|Wheat 

92|  Wheat 

93|  Wheat 

94|  Wheat 

951  Wheat 

96IWheat 

97|  Wheat , 

98|Oats 

99|Oats 

lOOIOats 

101|  Wheat 

102  Wheat 

1031  Wheat 


104|Barley 

lOoiBarley 

106|Barley 

I 

1071  Wheat 

10S!  Wheat 

1091  Wheat 

HOi  Potatoes 

llllPotatoes 

112!Potatoes 

1  Alfalfa,  Etc. 
1911 

1|  Alfalfa 

2!  Alfalfa 

3!  Alfalfa... 


4|Alfalfa 

51  Alfalfa 

6|  Alfalfa 

| 

7|  Alfalfa 

SI  Alfalfa 

9|  Alfalfa 


Class  of  soil 


Area 
-acres 


2600|Impervious   Clay   Loam 
2600|lmpervious   Clay   Loam 

3700]  Extremely  Sandy 
3«OU| Extremely  Sandy 
3700J  Extremely  Sandy 

3572|Medium  Clay  Loam 

3572|Medium  Clay  . 

3572iMedium  Clay  Loam 

2iMedium  Clay  Loam 

3572 1  Medium  Clay  , 

3572|Medium  Clay  '. 

3572iMedium  Clay  Loam  — 

3572|Medium  Clay  Loam 

3572|Medium  Clay  Loam 

3572 1  Medium  Clay  Loam 

2| Medium  Clay  Loam 

3572|Medium  Clay  Loam 

3572| Medium  Clay  Loam 

35i2iMedium  Clay  Loam 


3572|  Medium 
3572 1  Medium 
3572)  Medium 
3572|Medium 
3572 1  Medium 
3572|Medium 
3572!  Medium 

3572i  Medium 
3572|Medium 
3572!  Medium 

3572!  Medium 
35721  Medium 
3572 1  Medium 


Clay 
Clay 
Clay 
Clay 
Clay 
Clay 
Clay 

Clay 
Clay 
Clay 

Clay 
Clay 
Clay 


Loam 
Loam 
Loam 
Loam 
Loam 
Loam 
Loam 

Loam 
Loam 
Loam 

Loam 
Loam 
Loam 


3572!Medium  Clay  Loam 
3572|Medium  Clay  Loam 
3572! Medium  Clay  Loam 

3572 1 Medium  Clay  Loam 
3572|Medium  Clay  Loam 
3572IMedium  Clay  Loam 

3572! Medium  Clay  Loam 
3572!Medium  Clay  Loam 
3572IMedium  Clay  Loam 


3572!  Medium 
35721  Medium 
3572!  Medium 

I 

3800!  Shallow 
3800|Shallow 
SSOOiShallow 

37501  Medium 
3750!Medium 
3750!  Medium 


Clay  Loam. 
Clay  Loam. 
Clay  Loam. 

Clay  Loam. 
Clay  Loam. 
Clay  Loam. 

Clay  Loam. 
Clay  Loam, 
Clay  Loam. 


2.03 
2.03 


«o 

•s« 


4.091 
4.09| 


5-13| 
5-12| 


}jl 


Yield 
per  acre 


59    5 

61!  5 


.967 


3.91 

5.30 

6-20 

51 

4.34 

5.30 

6-22 

57 

4.66 

5.30 

6-20 

57 

a  

.189 

3.98 



n  

.092 

3.98 

6-1 

a  

.096 

3.98 

6-2 

"d 

a  

.097 

3.98 

6-2 

42 

ti  

.092 

3.98 

6-2 

4S 

n  

.091 

3.98 

6-2 

55 

i  

.092 

3.98 

6-3 

54 

.189 

3.98 

.094 

3.98 

6-1 

.093 

3.98 

6-2 

'42 

.095 

3.98 

6-2 

46 

.092 

3.98 

6-2 

42 

.094 

3.98 

6-2 

55 

.094 

3.98 

6-3 

54 

.189 

3.98 

.091 

3.98 

'e-i' 

.093 

3.98 

6-2 

'•42 

.090 

3.98 

6-2 

4X 

.094 

3.98 

6-2 

42 

.093 

3.98 

6-3 

54 

.096 

3.98 

6-3 

54 

.63 

3.98 

6-16 

.63 

3.98 

6-10 

'30 



.61 

3.98 

6-6 

42 

.990 

3.98 

6-9 

.!!!!! 

.982 

3.98 

6-5 

'i: 

.982 

3.98 

6-3 

34 

.985 

3.89 

6-21 

.965 

3.98 

6-18 

'  '';U 

.951 

3.98 

6-17 

BO 

.610 

3.98 

6-15 

.622 

3.98 

6-13 

'34 

3|  .789 
3|  .789 
3|  1.381 

0  .000 

1|  .479 

41j  3|  1.285 

5  1.516 

4  1.737 

7  2.558 

10|  2.820 


.641  |  3.98 


.630 
.630 
.610 


3.98 
3.98 
3.98 


6-14    40 


7-9 
7-2 
6-29 


I  I  I 

3.98|  5-10J105 

3.98  5-10128 

.965  I  3.98  5-11 128 


.943 


4.69 
5.38 
3.85 

3.72 
2.67 
3.76 


5.35 
5.35 
5.35 


.000 
.379 
1.184 
1.374 
1.861 
2.853 
3.156 

.000 
.417 
1.148 
1.451 
1.842 
2.161 


31.0    bu 
33.5    bu 

4.00  tons 
4.00  tons 
4.00  tons 

952.37  Ibs 
1108.69  Ibs 
1322.91  Ibs 
1371.13  Ibs 
1565.21  Ibs 

1472.53  Ibs 

1021.73  Ibs 

973.54  Ibs 

1095.74  Ibs 

1193.54  Ibs 
1389.47  Ibs 
1130.43  Ibs 
1351.06  Ibs 

797.87  Ibs 

1063.49  Ibs 
1285.71  Ibs 
1709.67  Ibs 
1833.33  Ibs 
1563.83  Ibs 
1139.78  Ibs 
968.75  Ibs 


.376  |  1333.33  Ibs 

.962  1501.58  Ibs 

1.533  I  1670.49  Ibs 

.460  |  1719.19  Ibs 

1.009  |  1450.10  Ibs 

1.402  |  1446.02  Ibs 


.555 

.953 

1.678 

.419 

.909 
1.788 

.539 
2.208 
3.644 


3  1.775 
6  3.329 
8  4.000 


1470.05  Ibs 
1842.48  Ibs 
1590.95  Ibs 

1754.09  Ibs 
1860.12  Ibs 
1893.91  Ibs 

7349.2  Ibs 
16738.0  Ibs 
16754.0  Ibs 


7534.0  Ibs 
10608.0  Ibs 
13233.0  Ibs 


5-9  |109|  4)  1.962 
5-1211161  6j  2.327 


I  I  I 
I  5.35!  5-31 
!  5.351  5-21 


5-8  1108!  5 


96 


2.549 


2.677 
3.263 


5.35|  5-19  119|  6|  3.786 


5.83 
5.57 
5.25 

4.56 
G.OO 
6.00 


tons 
tons 
tons 

tons 
tons 
tons 


REPORT   OF   STATE   ENGINEER. 


91 


Table  Showing-  Effects  of  Using-  Different  Amounts  of  Water  on  Grains, 
Alfalfa,  Etc.,  in  Edaho,  During-  the  Seasons  of  1910-11-12-13.—  Continued. 


Number 

Kind  of  cropc 

«                  Class  of  soil 

3   :      , 

Area 
—  acres 

Is 

3d 
$& 

*2 
^ 

0< 

Date  of  first 
irrigation 

J. 

£ 

•o 

1 

1 

I 

u 

/. 

c 

rt 
ti 

"c 
c 

Total  depth  irri- 
gation water 
applied—  feet 

Yield 
per  acre 

10 
11 
12 

!3 

14 
15 

10 
17 

18 

19 

20 
21 
22 

23 

24 
25 

26 

27 
28 

29 
30 
31 

32 
33 
34 

35 

36 

1 

2 
3 

4 

5 
6 

7 

s 

10 

11 

12 
13 

14 

15 

Alfalfa,  Etc. 
1911-Cont. 

Alfalfa 

3800|Medium  Clay  Loam  
3800|Medium  Clay  Loam  
3800IMedium  Clay  Loam  

3825  Medium  Clay  Loam  
}S25|Medium  Clay  Loam  
:>825|Medium  Clay   Loam  

3700|Very  Sandy  Loam  
3700  Very  Sandy  Loam  

4100lDeep  Clay  Loam  

4.17 

4.22 
4.96 

4.37 
4.19 

4.78 

2.65 
1.80 

9.98 
10.65 

5.45 

5.28 
5.73 

3.31 
4.32 
3.98 

3.37 
3.48 
3.37 

4.94 
4.21 
9.39 

5.43 
5.46 
4.53 

156.3 
40.49 

2.37 

6.54 

8.27 

4.58 

5.68 
7.72 
4.16 

1.83 
3.86 
3.23 

6.91 
6.05 
6.09 

4.85 
4.41 

3.19 
3.19 
3.19 

3.19 
3.19 
3.19 

5.30 
5.30 

5.80 
6.95 

6.95 
6.95 
6.95 

6.95 
6.95 
6.95 

6.80 
6.80 
6.80 

6.80 
6.80 
6.80 

6.80 
6.80 
6.80 

6.18 
6.18 

3.71 
3.71 
3.71 

3.71 

3.71 
3.71 
3.71 

3.71 
3.71 
3.71 

3.81 
3.81 
3.81 

3.81 
3.81 

6-4 
5-6 
5-8 

5-17 
5-13 
5-14 

5-10 
5-4 

5-20 
5-19 

5-22 
5-23 
5-22 

5-20 
5-20 
5-19 

6-3 
6-3 
6-3 

4-26 
4-25 
4-25 

4-21 
4-26 
4-25 

6-11 
6-15 

6-21 
6-24 
6-18 

8-1 

6-7 
6-9 
6-6 

6-5 
6-3 
6-1 

6-26 
6-18 
6-23 

6-3 
6-4 

80 
135 
135 

105 
112 
100 

119 
125 

lOb 

77 
1)4 
94 

88 
ID: 
10! 

10J, 
10"> 
10o 

111 
142 
141 

122 
119 
11! 

67 

t;r 

'»' 

22 
ffi 

51 

39 
53 
57 

'37 
34 

39 
00 

2 
4 
5 

3 
4 
5 

6 
6 

1 
8 

-1 
7 
G 

5 

7 

g 

8 
8 

(] 
11 
12 

7 
8 

c 

1 
] 

2 

1 

2 
3 
4 

2 

3 
-f 

i| 

!  3 

1.286 
3.194 
3.981 

1.309 
2.767 
3.211 

1.894 
2.611 

.993 
11.532 

5.402 
6.400 
7.224 

5.246 
6.611 
14.721 

1.535 
2.912 
4.114 

2.136 
3.511 
3.814 

3.257 
4.437 
6.040 

10.91 

8.562 

.735 
.871 
1.158 

.143 

.927 
1.436 
1.598 

.487 
1.427 
1.748 

.276 
.791 
!  1.214 
M 
1.655 

6.1      tons 
6.4      tons 
5.76    tons 

4.73    tons 
5.44    tons 
4.97     tons 

1.50     tons 
2.74    tons 

3.1      tons 
4.54    tons 

1.99    tons 
3.42    tons 
3.27    tons 

2.69    tons 
3.25     tons 
2.91    tons 

0.1      tons 
0.1      tons 
0.89    tons 

2.11    tons 
3.93    tons 
4.39     tons 

4.63    tons 
4.57    tons 
3.84    tons 

3.00    tons 

3.00    tons 

i 

67.5    bu 
72.1    bu 
82.9    bu 

* 

31.16  bu 
37.65  bu 
28.60  bu 

10.92  bu 
25.90  bu 
24.76  bu 

15.92  bu 
18.02  bu 
24.11  bu 

39.59  bu 
43.76  bu 

Alfalfa 

Alfalfa  

Alfalfa  

Alfalfa 

Alfalfa  
Alfalfa  

Alfalfa  
Alfalfa  
Alfalfa  

Alfalfa  
Alfalfa 

494:  \rerv  Gravelly  

4949)  Very  Gravelly  

4949|  Very  Gravelly  
4949  Very  Gravelly  

Alfalfa  
Clover  

4949  Very  Gravelly 

Clover  
Clover  

Alfalfa  
Alfalfa  
Alfalfa........ 

Alfalfa  
Alfalfa  
Alfalfa  

Timothy   & 
Clover  
Timothy  & 
Clover  

4949  Very  Gravelly  

4949  Very  Gravelly 

2607|Clav  Loam 

2607|Clay  Loam  

2607  Clay  Loam 

2607  1  Impervious  Clay  Loam. 
2607  Impervious  Clay  Loam. 
2607  !  Impervious  Clay  Loam. 

2547|  Dark  Sandv  Loam 

2547  j  Dark  Sandy  Loam  
25471  Dark  Sandy  Loam  .  . 

Timothy  & 
Clover  

5820|Very  Gravelly  
5330  'Very  Gravelly  

Alfalfa  and 
Grain 

Alfalfa  

Grain—  1912 
Wheat  
Wheat  

3800  Medium  Clay  Loam  
38001  Medium  Clay  Loam.... 
3800|Medium  Clay  Loam  — 

3825|Medium  Clay  Loam  

4000  Shallow  Gravelly  Clay.. 
4000|Shallow  Gravelly  Clay.. 
40001  Shallow  Gravelly  Clay.. 

4000  Shallow  Clay  Loam  — 
4000!Shallow  Clay  Loam.... 
4000IShallow  Clay  Loam  — 

3800  Shallow  Clav  Loam  — 
38001  Shallow  Clay  Loam.... 
3800|Shallow  Clay  Loam  — 

3750|Deep  Clay  Loam  
37501  Deen  Clav  Loam... 

Wheat  

Orchard  

Wheat 

Wheat    

Wheat  

Oats 

|Oats... 

lOats 

Wheat  
Wheat  
Wheat  

Wheat 

Wheat... 

*  Only  five  years  old,  very  small  yield,  not  .measured. 


92  REPORT  OF  STATE  ENGINEER. 

Table  Showing  Effects  of  Using  Different  Amounts  of  Water  on  Grains., 
Alfalfa,  Etc.,  in  Idaho,  During  the  Seasons  of  1910-11-12-13.— Continued. 


Number 

Kind  of  crop 

£                   Class  of  soil 

ft 

< 

Area 
—  acres 

Is 

3  a 

*& 

%$ 

*& 

,5<! 

Date  of  first 
irrigation 

Ir.  season  —  days 

If. 

= 

rt 

bx. 

u 
s 

Total  depth  irri- 
gation water 
applied—  feet 

Yi 
per 

16 

17 

is 
L9 
20 

21 

22 

23 

24 

26 

1 

28 

29 
30 

::i 

32 
33 

:;i 

35 
36 
37 

38 
39 
40 

11 

42 
43 

14 
15 
Iti 
•17 

4S 

49 
50 

r,i 

52 
53 
54 

55 

56 

57 
58 
59 
60 

Cl 
62 
63 

•VI 

66 

6fl 

Grain-1912 

4.78 
8.40 

.153 
.170 
.184 
.173 
.161 
.178 
.165 

3.98 
1.42 
3.57 

13.36 

5.40 
5.52 
5.73 

.689 
.636 
.625 

.186 

.097 
.088 
.094 
.091 
.093 
.089 

.186 

3.81 
3.81 

8.25 
8.25 
8.25 
8.25 
8.25 
8.25 
8.25 

8.25 
8.25 
8.25 

8.25 

8.51 
8.51 
8.51 

3.47 
3.47 
3.47 

3.47 
3.47 
3.47 
3.47 
3.47 
3.47 
3.47 

3.47 

6-2 
7-12 

*6-25 
6-25 
6-12 
6-12 
6-12 
6-12 

6-5 
6-7 
6-3 

6-19 

6-28 
6-29 
6-28 

5-29 
5-28 
5-27 

61 
c 

£ 

3G 

2 

39 
51 
54 

30 

40 
48 
49 

'23 

30 

3 

1 

0 

\ 

4 

1 

2 

1 

2 

3 

3 
3 

1 
2 

4 

0 
1 
3 

i 

1 

10 
0 

1 

3 

4 
6 

7 
10 

0 

l 
3 

4 
(1 
7 
10 

1 
3 
5 
7 

9 

1 
8 

2 
1 

7 

2.053 
.093 

.000 
.344 
.529 
.690 
.950 
.862 
1.042 

.780 
.951 
1.186 

2.473 

2.953 
3.236 
4.263 

.638 
1.087 
1.653 

.000 
.589 
1.244 
1.475 
1.806 
2.381 
2.638 

.000 
.343 
1.190 
1.179 
2.125 
2.216 
2.798 

.000 
.481 
1.273 
1.272 
1.815 
2.146 
2.436 

.418 

.857 
1.267 
1.577 
2.036 

.434 
1.061 
1.521 

.541 
1.943 
(  2.516 

42.05 

784.3 
1058.81 
1304.32 
1734.09 
1863.33 
2022.48 
3272.72 

34.92 
37.32 

38.38 

31.81 

76.7 
63.0 

74.7 

2367.3 
2336.1 
2326.7 

1087.7 
1104.2 
1530.6 
1525.4 
1444.3 
1652.3 
2022.3 

912.7 
1207.2 
1207.8 
1775.6 
1483.0 
1770.9 
1780.2 

1042.5 
1122.8 
1407.8 
1469.0 
1586.9 
1536.0 
1846.0 

2362.3 
2992.3 
3353.3 
3264.9 
3830.5 

2505.3 
4074.1 
4320.5 

112135.0 

118613.0 
116681.0 

Continued 
Wheat  

Orchard 

:;800  Shallow   Clay   Loam  

2763,  Impervious  Clay   Loam. 
2  <b3|  Impervious  Clay   Loam. 
^it>3  Impervious   Clay   Loam. 
^<b3jlmpervious   Clay   Loam. 
•iv-j  Impervious   Clay   Loam. 

Wheat  , 
Wheat 

Wheat  
Wheat  
Wheat 

Wheat  
Wheat  

Wheat  
Wheat 

^it)3;  impervious   Clay   Loam. 
2  itx;  impervious  Clay   Loam. 

Jt5i.ii  Impervious   Clay   Loam. 
2607J  Impervious   Clay   Loam. 
_'w«|  Impervious   Clay   Loam. 

26u<|Clay    Loam  

Wheat 

Wheat  

Oats  

4949jVery  Gravelly  

Oats 

4S)49iVery  Gravelly 

Oats  

4949iVery  Gravelly  

Wheat  
Wheat  

3572iMedium   Clay   Loam  — 
3572|  Medium    Clay    Loam.... 
3572iMedium  Clay   Loam  

o572|  Medium   Clay   Loam  — 
i572|Medium   Clay   Loam  — 
3572jMedium   Clay    Loam  — 
35<2|Medium   Clay   Loam  — 
3572J  Medium   Clay    Loam.... 
3572|Medium   Clay   Loam  
3572|Medium   Clay   Loam  — 

35i2|Medium   Clay    Loam 

Wheat  

Wheat  
Wheat  
Wheat  
Wheat  
Wheat  
Wheat  
Wheat  

Wheat  
Wheat  
Wheat  .... 

6-3 
6-3 
6-4 
6-4 
6-4 
6-4 

'SO 
28 

44 
44 
52 

35i2|Medium   Clay   Loam  
35<2|  Medium   Clay    Loam  

.091 
.092 
.088 
J)94 
.090 
.097 

.183 

3.47 
3.47 
3.47 
3.47 
3.47 
3.47 

3.47 

6-3 
6-3 
6-4 
6-4 
6-4 
.6-4 

'29 

28 
44 
44 
52 

Wheat 

Wheat 

3572|Medium  Clay   Loam  
3572|Medium   Clay    Loam  
3572|  Medium   Clay   Loam  
i 
3572|Medium   Clay    Loam 

Wheat  

Wheat  

Wheat  
Wheat  . 

3572|Medium  Clay   Loam  094 
3572  (Medium  Clay   Loam  090 
3572  Medium   Clay    Loam  092 
3572  Medium  Clay   Loam  086 
3572  Medium   Clay   Loam  .094 
3572|Medium   Clay   Loam  .084 

3572  Medium  Clay   Loam  383 
3572  (Medium  Clay   Loam  378 
3572  Medium   Clay   Loam  .383 
3572  Medium  Clay   Loam  <        .390 
3572  Medium  Clay   Loam  .334 

3572  Medium   Clay   Loam  .325 
35  •/'  Medium   Clay   Loam  326 
3572  Medium   Clay   Loam  .312 

3572  Medium   Clay   Loam  .627 
3572  (Medium   Clay   Loam  .628 
3572|Medium   Clay   Loam  '        .636 

3.47 
3.47 
3.47 
3.47 
3.47 
3.47 

3.47 
3.47 
3.47 
3.47 
3.47 

3.47 
3.47 
3.47 

3.47 
3.47 
3.47 

6-3 
6-3 
6-4 
6-4 
6-4 
6-4 

6-6 
6-6 
6-4 
6-5 
6-4 

6-11 
6-11 
6-12 
I 
7-1 
6-30 
6-29 

'29 
29 
44 
45 
52 

'36 

43 
49 
50 

'29 
37 

17 
44 
'  53 

Wheat  

Wheat  
Wheat  

Wheat  
Wheat  

Oats  

Oats  .  ... 

Oats  

Oats 

(Oats  

Barley  
Barley  
I  Barley 

Potatoes  
(Potatoes  
(Potatoes  

*  Only  five  years  old,  very  small  yield,  not  measured. 

REPORT   OF   STATE   ENGINEER. 


93 


Table  Showing  Effects  of  Using  Different  Amounts  of  Water  on  Grain, s 
Alfalfa,  Etc.,  in  Idaho,  During  the  Seasons  of  1910-11-12-13.— Continued. 


Kind  of  crop 


Alfalfa,  Etc. 
-1912 

HAlfalfa 

2|Alfalfa 

3|Alfalfa 

4 
5 


Alfalfa 

Alfalfa 

01  Alfalfa 

71  Alfalfa 

S'Alfalfa 

91  Alfalfa 

! 

101  Alfalfa 

HIAlfalfa 

121  Alfalfa 

I 

131  Alfalfa 

14!  Alfalfa 

151  Alfalfa 

1(5!  Alfalfa 

17|Alfalfa 

18|Alfalfa 

191  Alfalfa 

! 

20IAlfalfa 

21!  Alfalfa 

22i  Alfalfa 


231* 


Oats. 


I  Alfalfa 

24!Alfalfa 

25!  Alfalfa 

Grains.  Etc. 
-1913 

1  Alfalfa   

2|  Alfalfa 

31  Alfalfa , 

I 

5 1  Big:   "4 
6 1  Big    "4"   Oats 
I 

7|Wheat 

SlWheat 

9!  Wheat 

lOIWheat 

11 1  Wheat 

12|Wheat , 

131  Alfalfa 

14!  Alfalfa 

ISIAlfalfa 

16!Wheat 

17!  Wheat 

ISIWheat 


19  Big   "4" 

20  Big  "4" 
21!Big   "4" 


1 

I  < 


3572 1  Medium 
•%>i2\  Medium 
S5'<2  Medium 
$572|  Medium 
a?2i  Medium 
55<2l  Medium 


Class  of  soil 


Area 
acres 


Clay  Loam. 
Clay  Loam. 
Clay  Loam. 
Clay  Loam. 
Clay  Loam. 
Clay  Loam. 


SOOi  Meaium  Clay  Loam. 
;5800|Medium  Clay  Loam. 
5800!Medium  Clay  Loam. 

! 

:,S90|  Shallow  Clay  Loam. 
JSOOjShallow  Clay  Loam. 
38001  Shallow  Clay  Loam. 

! 

:*"<50|Deep  Clay  Loam 

3750|Deep  Clay  Loam  — 
3750|Deep  Clay  Loam 


H800|Shallow  Clay  Loam 


2607|Clay  Loam 

2607|Clay  Loam 

2607IClay  Loam 

'949| Porous  Gravelly. 
4949! Porous  Gravelly. 
4949 1 Porous  Gravelly. 

4949|Porous  Gravelly. 
4949|Porous  Gravelly. 
4949| Porous  Gravelly. 


I 

4550 1 Clay  Loam. 
4550|Clay  Loam. 
4550|Clay  Loam. 


4550iClay 
4550|Clay 
4550 1  Clay 

! 

4550 1  Clay 
4550 1  Clay 
4550!Clay 

4550|Clay 
45501  Clay 
4550!  Clay 


4850| Deep  Uniform  Clay. 
4850|Deep  Loam  Clay.... 
4850!  Deep  Loam  Clay  — 


Loam. 
Loam. 
Loam. 

Loam. 
Loam. 
Loam. 

Loam . 
Loam . 
Loam. 


4700|Deep  Unif'm  Clay  L'm. 
4700|Deep  TTnif'm  Clay  L'm. 
4700|Deep  Unif'm  Clay  L'm. 

Oatg  4700|Deep  TTnif'm  Clay  L'm. 
Oats  4700J Deep  Unif'm  Clay  L'm. 
Oatg  4700|Deep  Unif'm  Clay  L'm. 


d 


.372 

.585 
.372 
.569 
.369 
.580 

6.02 
7.49 
7.71 

4.24 
3.38 
3.75 

4.74 
4.82 
5.28 

14.28 

4.77 
3.62 
6.10 

4.36 
4.94 
4.75 


3.68 
2.65 
2.13 


2.70 
3.45 
3.44 


5.08 
5.06 
5.07 

3.01 
4.17 
3.03 

3.53 
6.06 
4.45 

7.52 
5.12 
6.60 

6.00 
5.16 
3.07 

4.73 

4.80 
4.90 


B 


3.47 
3.47 

3.47 

3.471 

3.471  5-14|  88 

3.47| 


5-27 
5-1 
5-1 
5-14 


Total  depth  ir 
gation  water 
applied  —  feet 


Yield 
per  acre 


I 

3.711 
3.711 
3.71| 

3.81| 
3.81| 
3.81| 

3.811 
3.811 
3.811 

! 
3.81| 

I 

8.25! 
8.25! 
8.25! 

8.51! 
8.51| 
8.511 


5-15|  86 

I  I  I 
5-22|  95|  3| 
5-24|  90 |  3| 
5-16|123|  61 

I  I  I 
5-14|107|  7 
5-14 1 107 1  6 
5-1311071  9 

I  !  I 
5-31!  97|  3| 
5-24!  92|  4| 
5-24|100|  4| 

I  I  ! 
5-271  98!  4! 

I  I  I 
5-171101!  6! 
5-16|  98|  6| 
5-191105!  7! 

I  I  I 
5-31!  75!  5| 
6-21|  55|  3| 


.615 
1.308 
2.059 
2.533 
2.931 
4.003 

1.708 
2.070 
3.381 

2.339 
2.513 
3.153 

1.064 
1.589 
1.799 

2.413 

1.870 
2.961 

2.887 


5695.0 
8003.0 
10828.0 
11317.0 
12506.0 
12612.0 


1.983 
2.027| 
6-1  I  75!  6!  2.582 


8.511 
8.51! 
8.51! 

I 

I 

| 

7.35! 
7.35! 
7.35) 

I 

7.35! 
7.35! 
7.35| 

I 

7.351 
7.351 
7.35! 

I 

7.351 
7.351 
7.35! 

I 

7.35! 
7.35! 
7.351 

I 

7.35! 
7.35! 
7.35! 

7.35! 
7.35! 
7.35| 


!     !' 


6-4  |  71 
6-5  !  71 
6-4  |  71 

I      I 

I      I 

! 

5-31!  90!  3! 

5-31!  871  41 

5-301  89|  6! 

I      I  I 

7-2  |...  1! 

6-30!  29!  2! 

6-28!  29|  21 

I      I  I 

6-22!  231  21 

6.24!  38!  3! 

6-6  !  58!  4! 

!      I  ! 

5-1011091  5| 

5-141  99!  4! 

5-101105!  5! 

!      I  ! 

5-29!  63!  2| 

5-7  1107!  3! 

5-4  1109!  4| 

6-30!  391  3! 

6-27!  35'  3| 

6-25!  43!  31 

I  I     I 

6-8  !  58!  3! 

6-6  I  471  3! 

6-5  |  49!  3| 


Ibs 
Ibs 
IDS 
Ibs 
Ibs 
Ibs 


3.047 
3.307 
6.721  I 

I 

I 

I 

1.28501 
1.9607! 
2.6876! 

I 

.3554! 

.8939! 

1.3291! 

I 

.9954! 
1.6230! 
2.3346! 

I 

2.34451 
2.6808! 
3.2882! 

i 

1.41901 

2. 4645 ' 

3.7354' 

| 

.7579! 

1.3089! 

2.2844! 

1 

.7833! 
1.2642! 
1.57221 


5.94  tons 
5.84  tons 
5.70  tons 

6.44  tons 
5.90  tons 
7.04  tons 

4.67  tons 
4.42  tons 
4.80  tons 

6.00  tons 

4.31  tons 
4.11  tons 
3.89  tons 

2.52  tons 
1.48  tons 
1.58  tons 

1.82  tons 
2.00  tons 
2.50  tons 


3.06  tons 
2.51  tons 
3.03  tons 

33.85  bu 
36.95  bu 

33.82  bu 

24.24  bu 
25.77  bu 
16.99  bu 

17.13  bu 
18.72  bn 
20.45  bu 

3.83  tons 
4.00  tons 
3.68  tons 

24.66  bu 

23.83  bu 
31.59  bu 

41.22  bu 
41.45  bu 
41.22  bu 


94 


REPORT  OF  STATE  ENGINEER 


Table  Showing  Effects  of   Using  Different  Amounts  of  Water  on  Grains, 
Alfalfa,  Etc.,  in  Idaho,  During  the  Seasons  of  1910-11-12-13.—  Continued. 


£       Kind  of  crop 
J5 

g 

3 

55 

«                   Class  of  soil 

s 
< 

Area 
—  acree 

Is 

3d 
*& 

8S 

*•%. 

G4 

Date  of  first 
irrigation 

Ir.  season  —  days 

•j. 

p. 

rt 

=f 

u 

0 

o 
Y+ 

Total  depth  irri- 
gation water 
applied  —  feet 

Yield 
per  acre 

Grains,  Etc. 
1913-Cont. 

22jAlfalfa 

4300|Deep   Clav    Loam 

3  82 

7.35 
7.35 
7.35 

7.35 
7.35 
7.35 

7.35 
7.35 
7.35 

7.35 
7.35 
7.35 

7.35 
7.35 
7.35 

7.86 
7.86 

7.86 

7.86 
7.86 
7.86 

7.86 
7.86 
7.86 

7.86 
7.86 
7.86 

7.58 

2.39 
2.39 
2.39 
2.39 
2.39 
2.39 
2.39 

2.39 
2.39 
2.39 

2.39 
2.39 
2.39 
2.39 

2.39 
2.39 
2.39 
2.39 
2.39 
2.39 
2.39 

5-26 
5-7 
5-4 

6-27 
6-24 
6-21 

6-7 
6-4 
6-5 

6-28 
6-27 
6-26 

5-31 
5-11 

5-28 

6-24 
6-25 

8-8 

7-12 
7-16 
7-18 

5-26 
5-27 
5-28 

5-20 
5-18 
5-22 

7-17 

'e-3' 
6-3 
6-4 
6-4 
6-4 
6-5 

'6-S' 
6-4 

6-4 
6-4 
6-4 
6-5 

74 
95 

112 

13 
17 
1? 

25 
40 
69 

17 
IS 
is 

70 
97 
72 

17 

37 
34 
33 

.... 
'.'.*. 

62 
68 

. 

4£ 

'35 

34 

48 
48 
53 

* 

34 

48 
48 
53 

;; 
4 
6 

•> 
2 

2 

2 
3 
3 

2 

1 

3 

4 
4 

1 

1 

2 

2 
2 
2 

1 
1 

1 

2 

t 

3 

\ 

\ 

4 

! 

0 

i 
2 

3 

4 

0 

I"? 

2 
3 
4 

I 

1 

1 

1.33271        3.94  tons 
2.3552|        6.11  tons 
3.5394!        6.10  tons 
D 
.47371      12.29  bu 
.88901      17.20  bu 
.92531        3.72  bu 

.65531      33.17  bu 
1.39491      35.32  bu 
2.18561      32.25  bu 

.70801      32.28  bu 
1.00161      51.57  bu 
1.2413!      46.80  bu 

.65141      34.42  bu 
1.28351      44.88  bu 
1.6017       49.33  bu 

.49301      39.7    bu 
.7139!      35.7    bu 
r 
1.64321      15.72  tons 
1 
1.2930!      33.3    bu 
1.7217!      36.5    bu 
2.91091      16.6    bu 

1.0440!       1.76  tons 
1.5148!        2.6    tons 

1.87781        2.84  tons 
r 
1.85711        3.9    tons 
1.7079!        4.1    tons 
1.93751        3.89  tons 

.33941300  boxes 

.00            0.00  Ibs 
.29891  1030.93  Ibs 
.5147!  1558.58  Ibs 
.5412!  1661.60  Ibs 
.97761  1703.88  Ibs 
1.1816!  1551.31  Ibs 
1.8633!  2571.43  Ibs 

.00    1       0.00  Ibs 
.26441  1109.42  Ibs 
.4749!  1839.30  Ibs 

.6913!  2273.27  Ibs 
1.1846!  1879.19  Ibs 
1.2551!  1888.89  Ibs 
2.1977!  3632.81  Ibs 

.00           0.00  Ibs 
.2576   1339.60  Ibs 
.4997   1922.60  Ibs 
.6903!  1377.91  Ibs 
.9300!  1321.32  Ibs 
1.0969!  2531.65  Ibs 
1.8359!  3542.48  Ibs 

23|  Alfalfa  
24|Alfalfa 

4300|Deep    Clay    Loam  
4300|Deep    Clay    Loam  

4850|Clav    Loam  

3.61 
5.77 

4.96 
4.36 
4.83 

3.92 
4.19 
4.34 

3.19 
3.18 
3.43 

4.11 
6.25 
2.27 

7.05 
2.38 

7.83 

4.35 
4.57 
3.91 

3.58 
2.69 
3.70 

3.12 

2.82 
4.05 

4.58 

.190 

.0873 
.0956 
.0987 
.0851 
.0838 
.0945 

.1925 
.0987 
.1033 

.0838 
.0894 
.0945 
.1024 

.1949 

.0851 
.0801 
.0987 
.0999 
.0869 
.0765 

25|  Wheat  
26|Wheat 

iSSftiniav     Loam... 

27  Wheat                   .  -IS^Iflnv     T.nnm 

28|Wheat  
29|  Wheat  
30|Wheat 

4300iMedium   Clay   Loam  
4300'Medium   Clay    Loam  
4ouO'Medium   Clay   Loam  

4300!  Medium   Clay    Loam  
4300|  Medium   Clay    Loam  
4300iMedium   Clay    Loam  

4300  Medium    Clay    Loam.... 
4300!  Medium    Clav    Loam  
4300[Medium    Clay    Loam.... 

45  <0  Deep    Unif'm    Clay    Loa' 
45/0  1  Deep   Unif'm    Clay   Loa' 

4570!Uniform    Clay    Loam  — 

45701  Deep    Uniform    Clay  
4570!Deep    Uniform    Clav  
4570'Deep    Uniform    Clay  

4700|Deep   Uniform   Clay  
4700|Deep   Uniform   Clay  
4700IDeep   Uniform   Clay  

4570|Deep   Uniform    Clay  
4570|Deep   Uniform    Clay  
4570IDeep   Uniform    Clay  

3825  Medium    Clay   Loam..... 

3572|  Uniform    Clay    Loam  .  .  . 
35721  Uniform    Clay    Loam... 
3572  Uniform    Clay    Loam... 
3572!  Uniform    Clay    Loam... 
35721  Uniform    Clay    Loam... 
3572|Uniform    Clay    Loam... 
3572|Uniform    Clay    Loam... 

3572IUniform    Clay    Loam... 
3572|Uniform    Clay    Loam... 
3572  (Uniform    Clay    Loam... 

3572  Uniform    Clay    Loam... 
3572|Uniform    Clav    Loam... 
3572  Uniform    Clay    Loam... 
3572  Uniform    Clay    Loam... 

35721  Uniform    Clay    Loam... 
3572!Uniform    Clay    Loam... 
35721  Uniform    Clay    Loam... 
3572|Uniform    Clav    Loam... 
3572IUniform    Clay    Loam... 
3572|Uniform    Clay    Loam... 
3572|Unif  orm    Clay    Loam  .  .  . 

31  Wheat  

32|  Wheat 

SS'Wheat  

34  1  Oats  . 

35  1  Oats 

36|0ats  
37  Wheat 

38lOats  

! 

39ISugar   Beets. 

40|  Oats 

4t|Oats  

42IOats  

43!  Alfalfa... 
44!Alfalfa 

45!  Alfalfa  

4HI  Alfalfa  
471  Alfalfa  

48!  Alfalfa  
49iQrchard  
501  Wheat  

51!Wheat  . 

52IWheat  
531  Wheat  
541  Wheat  
551  Wheat  
StilWheat  
| 
57|  Wheat  
581  Wheat  < 

SfllWheat  .  . 

60!  Wheat  .. 

«2|  Wheat  

f,3|  Wheat  
64!  Wheat  , 

65  1  Wheat 

661  Wheat... 

6-3 
6-4 
6-4 
6-4 
6-4 
6-5 

'si 

34 
48 
48 
53 

67'Wheat 

GSlWheat  

69!  Wheat  
70>Wheat  
71|Wheat  * 

REPORT  OF  STATE  ENGINEER. 


95 


Table  Showing  Effects  of  Using-  Different  Amounts  of  Water  on  Grains, 
Alfalfa,  Etc.,  in  Idaho,  During  the  Seasons  of  1910-11-12-13.— Continued. 


o*5 

ge 

IB 

n 

'C 

3d 

£n 

f 

i 

III 

Yield 

hi    Kind  of  crop 

•o  i                Class  of  soil 

rea 

°"W 

«3 

S*  ^ 

H 

8 

—  acres 

*2 

S.I 

1 

"r 

•o  aj 

per  acre 

3 

•<    1 

i 

S< 

a- 

C 

0 

o  c<  a 
£  bcrt 

Grains,  Etc. 

1913-  Cont. 

72|Barley  

3572|Uniform    Clay    Loam.,  i        .6541 
3572|Uniform    Clay    Loam               <JQOO 

2.39 
2oq 

5-31 

C     OA 

'  *M 

1 

.3902!  2057.79  Ibs 

73|Barley 

74|Barley..     .   . 

6019 

29Q 

Ic  on 

I 

75)  Barley 

3572!T7r»HVvY'TVi       Ola-ir       T  .no-m 

1  4073 

2  39 

5-1 

49 

1  3714 

1997  17   Ihu 

76  (Barley  

7466 

2  39 

4-30 

90  1 

2*67341  122288  Ibs 

77  1  Barley  

3572 

Uniform  Clay  Loam 

7400 

2  39 

4-29 

90 

2  7490|  1572  97  Ibs 

1 

78|Oats  

3572 

Uniform  Clav  Loam.. 

.9526    2.39 

5-fi 

:M 

1.2858 

1709.10  Ibs 

79|OatS                           |9K79.lTT«»'f/-wiTi      niov      T.ncim 

4943  |  2  39 

5  7 

so 

1  6123 

1793  fiK   IVic 

80'Oats  

3572IUniform    Clay    Loam.. 

.49431  2.39 

5-8 

81 

2  17353!  2120!  17  Ibs 

1 

1 

1 

81  1  Potatoes  
82|Potatoes  
83IPotatoes  

3572  1  Uniform    Clay    Loam.. 
3572iUniform    Clay    Loam.. 
3572iUnifnrm     (?lav     Lrmm 

.644      2.39 
.644      2.39 
.618      2.39 

7-12 
7-11 
7  10 

"32 

19 

iH  COCO 

.793  112251.55  Ibs 
1.250  118416.15  Ibs 
3.127  122095.47  Ibs 

I 

84|  Alfalfa  
85|  Alfalfa  
861  Alfalfa  

3572 

::r>72 

3572 

Uniform  Clay  Loam.. 
Uniform  Clay  Loam.. 
Uniform  Clay  Loam.. 

.4325 
.5271 
.4731 

2.39 
2.39 
2.39 

5-22 
5-21 
5-10 

86 

NT 
<>7 

3 

•1 
5 

1.1763110601.16  Ibs 
1.81941  9685.07  Ibs 
1.8194110410.06  Ibs 

871  Alfalfa  

3572]  Uniform    Clay    Loam.. 

.5032 

2.39 

5-9     98|  7 

1.9811 

11705.09  Ibs 

88|  Alfalfa  

3572!Uniform    Clay    Loam.. 

.4798    2.39 

5-9  |109|10 

3.0548113989.16  Ibs 

89|Alfalfa  3572iUniform    Clay    Loam..           .537212.39 

5-8  11181131  3.3388115022.34  Ibs 

The  preceding  tables  show  the  major  part  of  the  crop 
tests  that  were  included  in  the  four  seasons'  Duty  of  Water 
Investigation.  These  tables  give  a  brief  resume  of  the 
results  that  were  secured  from  415  plots  consisting  of  a 
total  area  of  1,842.5  acres  devoted  to  the  staple  crops  com- 
monly grown  in  South  Idaho.  The  majority  of  the  experi- 
ments was  conducted  with  alfalfa  and  the  grains,  but  all 
of  the  staple  crops  were  represented.  The  four  year's  in- 
vestigation, from  1910  to  1913  inclusive,  with  its  broad 
scope  has  thrown  much  new  light  upon -many  important 
irrigation  problems.  Tt  has  proven  that  many  old  theories 
have  an  utter  lack  of  foundation,  has  established  as  facts 
many  other  theories  and  has  laid  the  foundation  for  many 
new  ones.  The  chief  facts  that  have  been  brought  out  and 
emphasized  by  the  investigation  will  be  briefly  discussed 
later  in  the  report.  The  investigation  in  general  has  shown 
that  individual  experiments  cannot  be  depended  upon  for 
conclusions  for  the  reason  that  the  results  of  crop  tests 
are  often  affected  by  external  or  unknown  causes  and  that 
only  the  general  average  of  a  large  number  of  results 
secured  under  approximately  the  same  conditions  should 


96  REPORT  OF  STATE  ENGINEER. 

be  used.  The  experiments  included  in  this  investigation, 
however,  have  covered  four  seasons,  some  of  which  have 
been  wet  and  others  dry,  hundreds  of  different  tracts  of 
different  classes  of  soil  planted  to  different  crops  have 
been  included,  and  there  is  every  reason  to  believe  that 
a  general  average  of  such  a  large  number  of  results  secured 
during  these  four  seasons  will  be  found  to  be  very  reliable. 

It  was  found  early  in  the  investigation  that  there  was 
a  great  variation  in  the  water  requirements  of  the  various 
soils  and  crops.  The  soils  and  crops,  however,  so  far  as 
water  requirements  are  concerned,  have  seemed  to  auto 
matically  resolve  themselves  into  two  classes  each,  (1) 
those  requiring  the  least  water,  and  (2)  those  requiring 
the  most  water.  The  crops  belonging  to  the  first  class, 
those  requiring  the  least  water,  are  spring  and  winter 
grains,  potatoes,  and  clean  cultivated  orchards.  Those 
belonging  to  the  second  class  are  alfalfa  and  other  hay 
and  pasture  grasses.  The  soils  that  require  the  least  water 
are  the  medium  or  clay  and  silt  loam  soils  of  a  reasonable 
depth.  This  class  includes  adobe,  lava  ash,  clay  loam, 
and  fine  sandy  soils,  or  any  soil  of  &  reasonable  depth 
that  isjiot  porous.  The  soils  requiring  the  most  water 
are  the  porous  soils,  such  as  the  coarse,  sandy  and  gravelly 
soils.  For  the  purpose  of  illustration,  discussion  and  com- 
parison, the  soils  and  crops  will  hereafter  be  tabulated 
and  discussed  in  this  report  under  the  tAvo  above-men- 
tioned classes.  The  average  irrigated  soil  of  Idaho,  and 
of  most  other  western  states,  falls  in  the  medium  or  first- 
mentioned  class,  the  percentage  of  extremely  porous  irri- 
gated soils  being  quite  low.  The  tables  and  discussions  in 
regard  to  the  medium  soils  will  therefore  >be  of  mor^ 
use  and  interest  than  those  dealing  with  the  porous  soils. 

The  following  tables  have  been  compiled  from  results 
secured  throughout  the  investigation  with  the  medium  or 
less  porous  type  of  soil.  This  table  is  made  up  ft)  bv 
showing  Hie  average  results  secured  from  all  of  the  alfalfa 
plots  included  in  the  investigation  that  were  grown  on 
medium  soil,  and  (2}  by  selecting  the  plot  which  made 
the  maximum  yield  from  each  15-aere  experimental  tract, 
irrespective  of  the  amount  of  water  applied,  and  forming 
a  general  average  of  the  results  secured  from  all  of  them, 
some  26  in  number.  The  same  method  of  procedure  has 
been  followed  with  the  grains. 


REPORT  OF  STATE  ENGINEER. 


97 


Average  Results  Secured  on  Clay  Loam  Soils  During-  Four  Years 
1910  to  1913,  Inclusive. 


6"S 

T3 

^3 

GCS 

.£ 

.2  § 

Description  of  plots 

Crop 

•2 
o 

?! 

»£ 

beu 

«££ 

3 

u.<B 

SI 

5  rt  £ 

* 

6 

*  > 

*•  a. 

>    4iH- 

55 

<! 

^J  a 

<J 

Feet 

All  plots  included  in  investigation  
Plots  making1  maximum  yield   in  each 
exp.  irrespective  of  amount  applied.  . 

Alfalfa 
Alfalfa 

79 
26 

2.40 
2.73 

4.91  T 
5.47  T 

2.04  T 
2.00  T 

All  plots  included  in  investigation   

Grain 

221 

1.33 

36.38  Bu 

27  39  Bu 

Plots  making  maximum  yield  in   each 
exp.  irrespective  of  amount  applied.  .  . 

Grain 

60 

1.74 

44.92  Bu 

25.79  Bu 

It  is  believed  that  the  above  table  will  be  found  both 
useful  and  interesting,  as  it  showis  (1)  the  average  results 
secured  on  clay  loam  soils  from  all  of  the  alfalfa  plots  in- 
cluded in  the  investigation;  (2)  the  average  results  on  the 
same  type  of  soil  from  the  alfalfa  plots  which  made  the 
maximum  yield  in  each  experiment;  (3)  the  average  re- 
sults secured  from  all  of  the  grain  on  clay  loam  soils  in- 
cluded in  the  investigation;  and  (4)  the  average  results 
from  the  grain  plots  that  made  the  maximuan  yield  in  each 
experiment  on  this  type  of  soil. 

It  will  be  interesting  to  note  that  the  second  and  fourth 
lines  of  the  table  in  which  are  included  all  of  the  maxi- 
mum yields  produced,  irrespective  of  the  amounts  of  water 
applied,  show  that  the  maximum  yields  required  consider- 
ably more  water  than  was  applied  to  the  average  of  all 
plots.  This  strongly  indicates  that  at  least  up  to  a  certain 
point  the  greater  amount  of  water  applied,  the  greater  the 
yield.  The  last  column  of  the  table  gives  average  yield  per 
acre  foot  of  water  applied,  which  is  a  thorough  index  of 
the  efficiency  secured  from  the  water.  It  will  be  noted 
that,  while  the  most  water  produced  the  most  crop,  the 
amount  of  water  required  to  produce  the  average  maxi- 
mum yield  gave  less  efficiency  with  alfalfa  than  the  aver- 
age amount  applied  to  all  plots,  and  that  the  water  re- 
quired for  the  maximum  yield  of  the  grains  was  consider 
ably  less  efficient  than  the  average  applied  to  all  plotsi 
Consisting  of  so  many  plots  which  were  observed  during 
so  many  different  years  the  above  table  should  be  very 
dependable,  and  will  no  doubt  be  interesting  to  irrigation 
companies  and  others,  many  of  whom  have  become  too  en 
thusiastic  during  the  last  few  years  over  the  benefits  that 
are  obtained  from  an  abnormally  high  Duty  of  water. 


98  REPORT   OF   STATE  ENGINEER. 

ILLUSTRATION    OF    ALL    RESULTS    SECURED    ON 
CLAY  LOAM  SOILS  BY  THE  MEANS  OF  CURVES. 

The  proper  interpretation  of  the  results  secured  has 
been  very  difficult  at  times,  for  in  many  cases  the  results 
from  two  different  experiments  have  seemed  very  contra 
dictory.  These  freak  or  erratic,  and  sometimes  unex- 
plainable  results  are,  however,  bound  to  creep  into  agri- 
cultural experiments  and  serve  only  to  emphasize  the 
value  of  a  broad  investigation  extending  over  a  number  of 
years.  Due  to  the  great  variation  in  the  results  that  have 
sometimes  been  secured  from  even  more  or  less  similar 
experiments,  it  has  been  realized  that  no  two  men  could 
take  even  the  enormous  amount  of  data  that  have  been 
gathered  in  this  investigation  and  arrive  at  exactly  the 
same  results.  The  ultimate  results  would  be  bound  to  be 
more  or  less  influenced  by  personal  bias.  This  would  be 
especially  true  if  the  investigator  were  inclined  to  be  biased 
in  any  way,  for  some  experiments  show  surprisingly  large 
results  from  a  very  small  amount  of  water,  while  others, 
on  the  other  hand,  indicate  that  abnormally  large 
amounts  are  required  for  the  production  of  even  a  small 
crop. 

In  order  to  show  up  all  of  the  results  in  such  a  way  that 
they  may  be  compared  at  a  glance  and  in  such  a  man- 
ner as  to  positively  and  effectually  eliminate  all  personal 
equation,  all  of  the  results  secured  during  the  investiga- 
tion on  the  medium  soils  have  been  plotted  as  curves  and 
are  shown  on  the  two  following  plates.  The  two  factors 
which  have  been  considered  in  plotting  these  curves  are 
yields  per  acre  and  the  depths  of  water  applied  to  pro- 
duce them.  These  curves  show  many  factors  at  a  glance, 
and  it  is  believed  will  warrant  a  large  amount  of  careful 
study. 


V 
3* 

I: 


a      so      xs     f.o 


REPORT  OF  STATE  ENGINEER..  , 


101 


The  grain  curve  shows  the  yields,  seeded,  from, 
amounts  of  water  applied  to,  soifee  2$*  Jfc^iAj4V'$ 
The  points  are  widely  scattered,  showing  that  the  results 
secured  from  any  one  plot  cannot  be  depended  upon,  and 
that  only  an  average  of  the  results  from  a  large  number 
of  experiments  should  be  taken  into  consideration  when 
determining  the  duty  for  any  particular  soil  or  crop.    The 
grains  that  have  been  planted  and  grown  upon  soils  that 
have  been  fertilized  either  with  manure  or  by  the  plowing 
under  of  alfalfa  sod  have  been  plotted  as  triangles,  while 
those  grown  upon  ordinary  or  unfertile  soils  have  been 
plotted  as  small  circles.    The  grain  curve  shows  strikingly 
that  a  much  higher  efficiency  is  almost  invariably  secured 
from  the  water  when  applied  to  grain  planted  on  rich, 
fertile  soils.     While  the  points,  each  of  which  designates 
one  particular  field,  are  widely  scattered  on  the  sheet, 
there  are  so  many  of  them  that  it  seems  reasonable  that 
a  curve  plotted  across  the  sheet  striking  an  average  of 
the  points  and  showing  as  near  as  possible  an  average 
of  all  results  would  be  fair  and  accurate  enough  for  all 
practical  purposes.    Such  a  line  on  the  grain  curve  shows 
that  a  yield  of  about  14  bushels  per  acre  was  made  with 
no  water  application,  and  approximately  36  bushels  per 
acre  with  an  application  of  1.5  acre  feet  per  acre,  and 
proves  unquestionably  that  the  yield  of  grain  in  general 
may  be  expected  to  increase  as  the  water  applied  is  in- 
creased until  approximately  1.5  acre  feet  per  acre  has 
been  applied,  after  which  the  curve  shows  a  strong  prob- 
ability that  the  yields  would  decrease  if  more  water  were 
applied.     It  is  believed  that  the  results  shown  on   this 
sheet  cannot  be  questioned  or  controverted  by  anyone,  for 
personal  equation  can  have  absolutely  no  bearing  on  the 
proposition  in  any  way.     These  curves  show  a  striking 
agreement  with  the  result  tabulated  in  the  preceding  table 
on  page  97,  and  would  seem  to  prove  beyond  a  doubt 
that  at  least  1.5  acre  feet  per  acre  are  required  for  grain 
on  the  average  soils  of  South  Idaho,  and  that  when  more 
water  than  that  is  applied  there  is  not  only  not  a  propor- 
tional increase  in  yield  but  there  is  an  actual  decrease  in 
yield. 

The  alfalfa  curve  also  shows  a  general  tendency  toward 
increase  in  yield  as  the  water  applied  is  increased,  there 


102  REPOtn?  OF   STATE   ENGINEER. 


being  no  appreciable  break  in  the  curve  within  the  limits 
of  t&e  e£pferinl€to.ts.-  'Tins  curve  shows  without  question 
that  alfalfa  requires  much  larger  amounts  of  water  than 
grain,  that  a  maximum  yield  requires  an  abnormally  large 
application,  and  that  there  is  a  strong  and  regular  tend- 
ency for  alfalfa  to  increase  in  yield  as  the  amount  of 
water  application  is  increased  from  one  up  to  at  least 
four  acre  feet  per  acre.  This  curve  also  shows  a  striking 
agreement  with  the  alfalfa  columns  in  the  preceding  table. 
The  increase  in  the  yield  of  the  alfalfa,  however,  is  not 
proportional  to  the  increase  in  the  water  applied.  A  study 
of  the  curve  would  make  it  appear  somewhat  doubtful 
if  one  would  ever  be  warranted  in  applying  more  than 
three  acre  feet  per  acre  to  alfalfa  on  the  medium  clay 
loam  soil. 

WATER  REQUIREMENTS    AT    DIFFERENT    TIMES 
DURING  THE  SEASON. 

The  foregoing  curves  are  based  on  all  the  measurements 
made,  including  those  in  which  the  crops  were  evidently 
injured  by  the  lack  of  water  or  by  too  much  water,  as 
well  as  those  in  which  large  quantities  of  water  were  used 
without  any  appreciable  increase  in  yield.  They  do  not, 
therefore,  necessarily  indicate  a  proper  Duty  under  good 
practice.  Nor  do  they  show  the  proportion  of  the  water 
used  that  was  required  at  different  times  during  the  season. 

The  appropriations  and  contracts  of  nearly  all  of  the 
various  irrigation  companies  and  water  users  in  the  State 
call  for  a  continuous  flow  of  a  certain  number  of  cubic 
feet  per  second  throughout  the  irrigation  season.  The 
Duty  of  Water  Investigation,  however,  has  shown  very 
conclusively  that  the  water  requirements  of  all  crops  or 
combinations  of  crops  vary  greatly  at  different  times  dur- 
ing the  season,  and  that  a  uniform  continuous  flow  from 
the  beginning  to  the  end  of  the  season  is  not  conducive 
to  a  high  efficiency  from  the  water. 

In  order  to  throw  light  upon  this  important  subject  and 
furnish  reliable  data  for  use  in  designing  storage  projects 
and  pumping  plants  where  the  actual  maximum  seasonal 
demand  must  be  known  before  the  economic  size  of  plant 
or  reservoir  can  be  determined  upon,  the  following  tables 
have  been  compiled  from  the  data  secured.  All  tracts 


REPORT   OF   STATE   ENGINEER. 


108 


or  plots  that  have  made  any  appreciable  decrease  in  the 
yields  because  of  water  shortage  or  excessive  application 
have  been  eliminated.  Other  tracts  have  also  been  arbi- 
trarily eliminated  where  an  abnormal  or  unjustifiable  in- 
crease in  the  amount  of  water  was  required  in  order  to  se- 
cure a  very  small  increase  in  the  yield,  and  it  is  believed 
that  the  data  in  these  tables  will  furnish  a  basis  from 
which  the  proper  and  economic  duty  for  any  particular 
project  can  be  determined. 

For  convenience  and  ready  comparison  four  tables  have 
been  made  of  thcj  results  secured  during  the  four  years,  by 
separating  the  crops  and  soils  into  two  classes  each,  viz: 
(1)  grain  on  medium  clay  and  sandy  loam  soils;  (2) 
alfalfa,  clover,  and  pasture  on  medium  clay  and  sandy 
loam  soils;  (3)  grain  on  porous,  coarse  sandy  and  gravelly 
soils;  (4)  alfalfa,  clover,  and  pasture  on  porous,  coarse 
sandy,  and  gravelly  soils. 

Summary  of  Depths  of  Water  Applied  by  Months  to  One  Hundred  and 
Seventy-one  Fields  of  Grain  and  Alfalfa  on  Medium  Clay 

and  Sandy  Loam  Soils. 
Altitudes  ranging  from  2400  to  5000  feet.      Seasons  of  1910,  1911,  1912  and  1913. 


Season 

o2 

-  o 

Ap 

ril 

May 

June 

July 

Aug. 

Sept. 

2* 
Si 

I"5- 

1-iS 

16-30 

£* 

119  Fields  of  Grain 
1910  

^1 

.3210 

.6000 

5460 

(»780 

1  5450 

1911 

30 

0270 

6540 

4780 

•  0100 

1  1690 

1912     

25 

.9420 

.6550 

0460 

1  64^0 

1913  

33 

0392 

.2062 

.5434 

.5941 

.2268 

1.6097 

Average  

.0098 

.1385 

.6849 

.5683 

.0902 

1  .  4917 

Per  cent  of  total  . 

.66 

9.28 

45.91 

38  10 

6  05 

100  00 

52  Fields  of  Alfalfa— 

1910  
1911  

15 
13 

.0600 

.0210 
.0350 

.5540 
.4930 

.7390 
.2930 

.6530 
.9130 

.6070 
.(>970 

.0650 
.2480 

2.6990 
2.6790 

1912  
1913 

11 
13 

.4910 
8627 

.5030 

2284 

.6210 

7422 

.6080 
3854 

.0380 
0175 

2.2610 
2  236^ 

Average 

0150 

0140 

6002 

4408 

7323 

5744 

0921 

i  4688 

Per  cent  of  total     

61 

57 

24.31 

17.86 

29  66 

23  26 

3  73 

100  00 

The  above  tables,  as  has  been  stated,  include  only  plots 
that  have  demonstrated  by  the  yields  produced  that  they 
were  cultivated  and  irrigated  in  the  best  possible  manner, 
and  the  average  amount  applied  during  the  4-year  period 
is  shown  at  the  bottom  of  the  last  column  of  each  table, 
and  is  that  amount  which  the  author  deems  the  best  econ- 


104  REPORT  OF  STATE  ENGINEER. 

omic  amount  for  the  crop  in  question  when  planted  on  a 
medium  clay  loam  on  average  South  Idaho  soil.  The 
amounts  of  water  tabulated  in  the  above  tables  are  the 
amounts  that  have  been  actually  retained  upon  the  fields 
in  question,  the  waste  water  having  been  deducted. 

The  grain  table  shows  a  Duty  of  almost  exactly  1.50 
acre  feet  per  acre,  of  which  .0098  acre  feet,  or  .66  per  cent 
are  required  during  the  last  half  of  April ;  .1385  acre  feet, 
or  9.28  per  cent  during  May ;  .6849  acre  feet,  or  45.91  per 
cent  during  June;  .5683  acre  feet,  or  38.10  per  cent  during 
July;  and  .0902  acre  feet,  or  6.05  per  cent  during  August, 
there  having  been  no  water  required  for  grains  in  Septem- 
ber during  the  period  covered  by  the  investigation. 

The  alfalfa  table  shows  a  water  requirement  of  2.46S8 
acre  feet  per  acre,  which  is  to  all  intents  and  purposes  2.5 
acre  feet  per  acre,  of  which  .029  acre  feet,  or  1.18  per  cent 
is  required  during  April ;  .6002  acre  feet,  or  24.31  per  cent 
during  May ;  .4408  acre  feet,  or  17.86  per  cent  during  June ; 
.7323  acre  feet,  or  29.66  per  cent  during  July;  .5744  acre 
feet,  or  23.26  per  cent  during  August ;  and  .0921  acre  feet, 
or  3.73  per  cent  during  the  first  one-half  of  September. 

It  is  believed  that  the  two  tables  immediately  preceding 
will  be  found  the  most  valuable  and  most  dependable  of 
'any  that  it  is  possible  to  include  in  this  report,  for  they 
are  a  general  summary  of  the  four  years'  investigation  in 
Idaho. 

Porous  soils  were  included  in  the  investigation  during 
the  seasons  of  1910  and  1911,  and  a  table  which  follows 
later,  page  109,  shows  the  average  results  secured  on 
these  soils. 

It  is  believed  that  the  results  secured  are  typical  in 
every  way  of  what  might  be  expected  from  porous  soils 
and  that  they  may  be  safely  used  in  such  connection.  It  will 
be  seen  from  the  tables  that  the  amounts  required  for  al- 
falfa and  the  grains  on  these  soils  bear  practically  the 
same  relationship  to  each  other  as  they  do  when  the  crops 
are  planted  on  the  medium  soils,  and  that  a  far  larger 
amount  of  water  is  required  for  the  successful  irrigation 
of  the  crops  than  is  required  when  they  are  planted  on 
the  medium  Idaho  soils. 


REPORT  OF  STATE  ENGINEER. 


105 


COMPARATIVE   AREAS  DEVOTED   TO    DIFFERENT 

CROPS. 

In  view  of  the  great  difference  in  the  water  require- 
ments of  (a)  the  grains,  potatoes  and  clean  cultivated 
orchards,  and  of  (b)  alfalfa,  the  clovers  and  pasture,  it 
is  apparent  that  a  knowledge  must  be  had  of  the  com- 
parative areas  that  will  ultimately  be  devoted  to  these 
different  crops  before  the  proper  Duty  can  be  determined 
for  any  project. 

The  acreages  planted  to  these  crops  will,  of  course,  de- 
pend in  each  case  upon  the  soil,  climate,  proximity  to 
market,  and  local  conditions  obtaining  in  each  case,  but 
is  best  determined  by  a  survey  of  well  developed  projects 
that  are  and  have  been  operating  under  normal  condi- 
tions. It  has  frequently  been  assumed  by  those  best  in- 
formed in  regard  to  irrigation  conditions  that  most  of 
Idaho's  projects  will  be  about  equally  divided  between 
the  two  above  classes  of  crops,  but  in  order  to  demon- 
strate this  matter  more  fully  a  census  has  been  secured 
of  the  acreages  of  the  various  crops  on  the  South  Side 
Twin  Falls  Tract  for  1912  and  1913,  and  of  seven  Boise 
Valley  canals  for  1911  and  1912  .  A  brief  summary  of  this 
census  is  given  in  the  following  table.  The  census  of  the 
South  Side  Twin  Palls  Project  was  made  by  the  ditch 
riders  under  the  supervision  of  General  Manager  Harlan, 
and  that  of  Boise  Valley  canals  was  secured  by  our  own 
assistants. 

Table  Showing-  Comparative  Areas  Devoted  to  Different  Crops. 


District 

u 
rt 
o> 
> 

Hay 
and  Pasture 

Grain, 
Potatoes  and 
Orchard 

Total—  acres 

Area  — 
acres 

Percent 
of  total 

Area- 
acres 

Percent 
of  total 

Twin  Falls  South  Side  Project  
Twin  Falls  South  Side  Project  

Seven  Boise  Valley  Projects  
Six  Boise  Valley  Projects  

1912 
1913 

1911 
1912 

70,043 
67,115 

*26,2S3 
24,492 

47.55 
44  95 

*59.75 
57.90 

77,266 
82,1% 

17,684 
17,804 

194  ,950 

52.45 
55.05 

40.25 
42.10 

147,309 
149,311 

43,937 
42,2% 

382,853 

Total 

187,903 

49.08 

50.92 

Per  cent  of  total  

*  This  area  and  percentage  was  somewhat  above  normal  on  account  of  the  compara- 
tively larg-e  amount  of  bottom  land  that  was  seeded  to  pasture  under  some  of  these 
canals. 


106 


&EPOBT   OF   STATE   ENGINEER. 


In  view  of  the  fact  that  the  percentage  shown  in  the 
above  table  agrees  with  the  best  information  obtainable 
along  this  line,  it  is  considered  that  it  is  fair  to  assume 
that  any  normal  project  in  South  Idaho  will  ultimately 
be  devoted  to  approximately  equal  areas  of  (1)  the  grains, 
potatoes  and  orchards,  (2)  alfalfa,  clover  and  pasture, 
or  crops  requiring  a  similar  amount  of  water.  Assuming 
that  this  will  be  the  case,  the  average  Duty  for  a  normal 
Idaho  project  should  be  found  by  averaging  the  proper 
and  economic  Duty  for  the  two  above  named  classes  of 
crop  on  the  particular  type  of  soil  involved.  The  follow- 
ing table  has  been  constructed  in  this  manner  by  averag- 
ing the  Duty  that  has  been  determined  for  grain  and  for 
alfalfa  on  the  medium  or  average  soil  of  South  Idaho 
for  all  four  years  of  the  investigation. 

Summary  of  Depths  of  Water  in  Feet  Applied  by  Months  to  One  Hun 
dred  and  Seventy-one  Selected  Fields  of  Grain  and  Alfalfa 

on  Medium  Clay  and  Sandy  Ivoam  Soils. 
Altitude  ranging  from  2400  to  5000  feet.     Seasons  of  1910,  1911,  1912,  1913. 


Crop 

c 

of 

Ap 

ril 

May 

June 

Juljr 

Aug-. 

Sept. 

£c 
"3* 

% 

Is- 

1-15 

16-30 

1-15 

£S 

Alfalfa   

1910 
1910 

15 
31 

.0600 

.0210 

.5540 
3210 

.7390 
6000 

.6530 
5460 

.6070 
0780 

.0650 

2.6990 
1.5450 

Alfalfa   

Grain 

1911 
1911 

13 
30 

.0350 

.4930 
0270 

.2930 
6540 

.9130 
4780 

.6970 
0100 

.2480 

2.6790 
1.1690 

Alfalfa   
Grain            .       .   . 

1912 
1912 

11 

25 

.4910 

.5030 
9420 

.6210 
6550 

.6080 
0460 

.0380 

2.2610 
1.6430 

Alfalfa          

1913 

13 

.8627 

.2284 

.7422 

.3854 

.0175 

2.2362 

Grain  . 

1913 

33 

0392 

.2062 

.5434 

.5941 

.2268 

1.6097 

Average  

.0075 
38 

.0119 
60 

.3693 
18  65 

.5628 
28  42 

.6504 
y>  85 

.3323 
16  78 

.0460 
2  32 

1.9802 
100.00 

The  above  table  is  a  general  average  of  the  results  that 
have  been  secured  on  the  average  soil  of  South  Idaho  dur- 
ing the  entire  four  years'  investigation,  and  it  is  considered 
that  it  is  by  far  the  most  important  table  included  in  this 
report.  It  is  in  reality  the  "meat"  or  final  result  of  the 
entire  four  years'  Duty  of  Water  Investigation  and,  as 
the  soU  in  question  is  an  average  of  that  which  is,  or  wilJ 
be,  included  in  at  least  75  per  cent  of  Idaho's  irrigation 
projects,  and  probably  in  the  same  per  cent  of  the  projects 
in  many  other  states,  it  is  believed  that  this  table  will  be 
used  far  more  than  the  following  one  which  shows  the  aver- 
age amounts  applied  to  porous  soils. 


REPORT  OP  STATE  ENGINEER. 


107 


AMOUNT  OF  WATER    REQUIRED  EACH   MONTH  OF   THE   IRRIGATION  SEASON 

BY  A  PROJECT  DEVOTED  TO  EQUAL  AREAS  OF   GRAIN  AND  HAY 

ON  MEDIUM  CLAY  OR  SANDY  LOAM  SOIL. 

As  this  table  includes  the  results  of  171  selected  tracts 
of  this  particular  type  of  soil  covering  a  period  of  four 
years,  thus  effectively  eliminating  the  individual  differ- 
ences of  the  seasons,  of  irrigators  and  of  the  tracts  them- 
selves, it  is  considered  that  the  results  contained  in  it  will 
be  found  to  be  very  dependable. 

It  shows  that  a  project  devoted  to  equal  areas  of  (1) 
grain,  orchards,  and  general  root  crops,  and  (2)  hay,  in- 
cluding alfalfa,  clover,  timothy  and  pasture  on  average 
South  Idaho  soil  should  furnish  sufficient  water  so  that 
an  average  of  1.98  acre  feet  can  be  retained  on  each  and 
every  irrigated  acre  during  the  season.  Of  this  amount, 
which  is  to  all  intents  and  purposes  an  annual  or  seasonal 
Duty  of  2  acre  feet  per  acre,  exclusive  of  the  precipitation, 
0.0075  feet  in  depth  or  0.38  per  cent  will  be  required  dur- 
ing the  first  half  of  April;  0.0119  feet  in  depth  or  0.6  per 
cent  will  be  required  in  the  last  half  of  April ;  0.3693  feet 
in  depth  or  18.65  per  cent  during  May;  0.5628  feet  in 
depth  or  28.42  per  cent  during  June ;  0.6504  feet  in  depth 
or  32.85  per  cent  during  July;  0.3328  feet  in  depth  or  16.78 


108  REPORT  OF  STATE  ENGINEER. 

per  cent  during  August;  and  0.0460  feet  in  depth  or  2.32 
per  cent  during  the  first  half  of  September,  making  a  to- 
tal of  1.9802  acre  feet  per  acre,  or  100  per  cent 
for  the  season.  The  above  amounts  are  based  strictly 
upon  the  crop  needs  as  shown  by  the  Duty  of  Water  Inves 
tigation,  and  includes  nothing  for  stock  water  or  that 
which  may  be  required  for  domestic  purposes  or  for  losses 
in  conveyance,  nor  is  there  any  included  for  late  fall  or 
winter  irrigation.  If  the  data  in  this  table  are  to  be  used 
in  alloting  water  to  an  irrigation  project  this  factor  must 
be  taken  into  consideration,  if  water  is  to  be  used  for  the 
above  mentioned  purposes. 

This  table  shows  that  there  is  small  need  for  water 
either  earlier  than  May  or  later  than  August;  and  that  in 
all  of  the  tracts  considered  there  has  been  no  need  for 
water  during  the  four  years  of  the  investigation  by  either 
alfalfa  or  grain  during  the  last  half  of  September.  It 
shows  also  that  over  61  per  cent  of  the  total  water  re- 
quired during  the  season  is  required  in  the  61  day  period 
during  June  and  July.  This  table  will  be  found  very  use- 
ful to  those  called  upon  to  design  storage  projects,  as  a 
variety  of  curves  may  be  worked  up  from  it,  which,  taken 
in  connection  with  the  hydrograph  of  the  discharge  of  the 
stream  from  which  the  supply  is  to  be  derived,  will  show 
how  much  of  the  water  it  will  be  necessary  to  store.  It 
will  also  be  of  great  help  in  the  designing  of  pumping 
plants,  and  particularly  in  determining  the  size  of  the  var- 
ious pumping  units  that  should  be  installed. 

The  table  shows  conclusively  that  any  large  pumping 
plant  should  consist  of  more  than  one  unit,  and  possibly 
as  many  as  three  or  four,  for  a  unit  that  could  economical- 
ly supply  the  maximum  demand  during  June  and  July 
could  not  possibly  be  economically  operated  with  the  de- 
creased demands  of  May  and  August.  This  feature  must 
always  be  given  consideration. 

The  table  seems  to  prove  conclusively  that  the  uniform 
continuous  flow  method  of  delivery  is  exceedingly  waste- 
ful, for  if  a  right  called  for  a  uniform  continuous  flow 
throughout  the  season  with  an  allotment  per  acre  of  suf- 
ficient size  to  deliver  the  required  amount  during  June  and 
July,  a  large  proportion  of  the  amount  delivered  could  not 
be  used  economically,  and  would  be  wasted  during  the 
months  of  April,  May,  August,  and  September.  While  if. 


REPORT  OF  STATE  ENGINEER. 


109 


on  the  other  hand,  the  uniform  continuous  flow  were  of  the 
size  required  to  deliver  the  2  acre  feet  required  during  a  6 
months'  or  even  a  4  months'  irrigation  season,  there  would 
still  be  more  water  than  is  actually  required  during  the 
early  and  late  part  of  the  season,  and  considerably  less 
than  is  required  during  the  months  of  June,  and  July, 
when  61  per  cent  of  the  total  season's  supply  must  be  de- 
livered if  profitable  returns  are  to  be  expected. 

The  following  table  gives  a  general  summary  of  the  re- 
sults that  have  been  obtained  upon  the  porous  sandy  and 
gravelly  soils.  This  table  has  been  constructed  by  aver 
aging  the  Duty  that  has  been  determined  for  grain  and  al- 
falfa on  these  soils  during  the  first  2  years  of  the  investi- 
gation, there  not  having  been  a  sufficient  number  of  tracts 
on  this  type  of  soil  experimented  upon  during  the  last  2 
years  of  the  investigation  to  be  included  in  such  a  sum- 
mary table. 

Summary  of  Depths  of  Water  in  Feet  Applied  by  Months  to  Thirty- 
one  Selected  Fields  of  Grain  and  Alfalfa  on  Porous 

Sandy  and  Gravelly  Soils. 
Altitudes  ranging-  from  2600  to  5800  feet.     Seasons  of  1910  and  1911. 


Crop 

c 
o 

C0 

^ 

Ap 

ril 

May 

June 

July 

Aug-. 

Sept. 

u 

£s= 
,_,  o 

Ss. 

z& 

1-15 

16-30 

gl 

Alfalfa    

1910 

7 

5310 

1  1200 

1  6910 

1  9570 

1  1310 

6  4300 

Grain  

1910 

10 

.0290 

1.4430 

.6550 

.3580 

2.4850 

Alfalfa   

1911 

6 

.1820 

.9160 

1.8430 

l.llfO 

2.2650 

.2560 

6.5770 

Grain   

1911 

g 

8980 

1  0570 

9430 

2  8980 

Average  

.1782 

.5163 

1.4687 

1.1960 

1  .  1743 

.0640 

4.5975 

Per  cent  of  total  . 

3  88 

11  23 

31  9S 

%  01 

25  54 

1  39 

100  00 

This  table  shows  that  porous  soils  require  a  larger 
amount  for  their  efficient  irrigation  than  the  medium 
soils,  and  indicates  that  a  Duty  of  approximately  4.6 
acre  feet  per  acre  per  annum  will  be  required,  of  which 
3.88  per  cent  will  be  required  during  the  last  half  of  April ; 
11.23  per  cent  will  be  required  during  the  month  of  May; 
31.95  per  cent  during  June;  26.01  per  cent  during  July; 
25.54  per  cent  during  August;  and  1.39  per  cent  during  the 
first  half  of  September,  making  a  total  of  4.5975  acre  feet, 
or  100  per  cent  during  the  season. 

The  preceding  tables  showing  the  average  Duty  that  has 
been  arrived  at  for  projects  with  either  medium  or  porous 
soils  are  considered  the  most  important  in  the  report; 


110  REPORT  OF  STATE  ENGINEER. 

These  and  the  many  factors  which  have  a  bearing  upon  the 
Duty  of  Water  will  be  discussed  more  thoroughly  later  in 
the  report. 

INVESTIGATION  OF  USE  OF  WATER  UNDER  COM- 
PLETE CANAL  SYSTEMS  IN  BOISE  AND  UPPER 
AND  MIDDLE  SNAKE  RIVER  VALLEYS. 

It  is  considered  that  the  investigation  which  has  been 
carried  on  will  furnish  a  very  accurate  idea  of  the  proper 
and  economic  field  Duty  for  the  different  soils,  but  it  has 
been  realized  that,  in  addition  to  this,  a  knowledge  of  the 
losses  that  are  usually  experienced  in  transmitting  and 
delivering  the  water  must  be  had  before  it  will  be  pos1- 
sible  to  design  an  efficient  and  economical  project.  In 
order  to  secure  a  better  knowledge  of  this  factor  it  was 
decided  to  extend  the  investigations  by  measuring  the 
total  amount  of  water  diverted  by  several  typical  large 
canals  and  then  secure  the  acreage  under  them  devoted  to 
the  different  crops,  and  in  this  way  determine  the  gross 
amount  that  it  is  found  necessary  to  divert  for  the  irri- 
gation of  large  areas  under  normal  conditions,  where 
waste  water  and  that  used  for  domestic  purposes,  etc., 
would  all  be  considered. 

It  had  been  planned  to  do  this  work  during  1912,  along 
with  a  lesser  number  of  the  usual  Duty  of  Water  experi- 
ments, as  a  rounding  out  of  the  entire  investigation,  but 
it  was  found  in  the  fall  of  1911  that  the  local  branch  of 
the  U.  S.  Reclamation  Service  had  been  making  a  careful 
measurement  of  all  water  diverted  by  the  principal  canals 
of  the  Boise  Valley  during  the  season,  and  it  was  decided 
to  start  this  line  of  investigation  at  once,  provided  a  suit- 
able arrangement  could  be  entered  into  with  the  U.  S. 
Reclamation  Service  for  securing  these  measurements. 
These  arrangements  were  perfected  and  an  agreement 
was  entered  into  between  the  two  departments,  whereby 
our  department  was  to  make  a  careful  canvass  of  the  crop 
acreages  under  the  canals  and  exchange  the  data  so  col- 
lected with  the  U.  S.  Reclamation  Service  for  the  discharge 
tables  that  had  been  secured  by  them. 

Accordingly,  an  experienced  man  was  placed  in  the 
field,  who  made  a  careful  and  painstaking  canvass  of  the 
areas  devoted  to  the  different  crops,  together  with  the  un- 
irrigated  area,  and  such  other  data  as  was  thought  neces- 
sary. This  crop  census  was  made  of  all  lands  under  the 


REPORT  OF  STATE  ENGINEER. 


Ill 


following  canals :  Settlers',  Farmers'  Co-operative,  River- 
side, Farmers'  Union,  Pioneer,  Eureka  and  Boise  Valley. 
On  account  of  the  great  expense  that  would  have  been 
involved  in  making  a  survey,  the  acreages  were  obtained 
by  a  careful  and  systematic  house-to-house  canvass  or 
census.  It  is  believed  that  this  canvass  was  especially  ac- 
curate and  fully  as  reliable  as  any  stadia  survey  that 
could  be  made,  for  the  following  reasons : 

(1)  A  much  larger  area  could  be  taken  into  consid- 
eration on  account  of  the  expense  that  would  be  involved  by 
a  survey,  which  increase  in  area,  it  is  believed,  materially 
reduced  the  percentage  of  error  from  all  causes. 

(2)  Accurate  maps  of  the  canal  systems  were  secured, 
and  as  the  farms  were  regular  in  shape  and  not  cut  up  by 
waste  land,  the  total  area  under  the  canals  was  easily  se- 
cured. 

(3)  The  areas  devoted  to  individual  crops  were  ob- 
tained from  the  farm  operators  on  the  ground,  and  as 
the  areas  of  the  individual  crops  had  to  equal  the  total 
area  of  the  farm,  in  each  case  a  very  good  check  was  ob- 
tained upon  the  accuracy  of  the  canvass. 

Water  Measurements. 

All  water  measurements1  during  1911  were  made  by  the 
local  branch  of  the  U.  S.  Reclamation  Service.  Those  of 
1912  were  made  by  our  own  hydrographers.  The  discharge 
of  the  canals  has  been  calculated  from  daily  gauge  read- 
ings and  rating  curves,  which  were  made  up  from  a  large 
number  of  current  meter  measurements  made  by  from  two 
to  six  hydrographers  at  each  station.  These  rating  sta- 
tions were  very  carefully  selected,  and  as  a  very  large 
number  of  careful  ratings  were  made  at  each  station,  it  is 
believed  the  discharge  tables  given  herein  are  very  ac- 
curate. The  water  measurements  of  the  South  Side  Twin 
Falls  Canal  were  secured  from  the  local  branch  of  the 
TT.  S.  Geological  Survey,  and  the  crop  census  from  General 
Manager  Geo.  Harlan,  who  had  caused  a  census  to  be  taken 
during  both  years  by  his  ditch  riders.  A  brief  description 
of  each  canal  system  follows,  together  with  the  data  that 
were  secured  from  it  during  the  seasons  of  1911  and  1912. 

Riverside  Canal. 

The  Riverside  Canal  diverts  water  from  the  south  side 
of  the  Boise  River  just  above  Oaldwell.  This  canal  irri- 
gates approximately  9,000  acres  of  bench  lands,  consisting 


112  REPORT  OF  STATE  ENGINEER. 

principally  of  the  typical  volcanic  ash  or  clay  loam  soil 
common  to  the  greater  portion  of  South  Idaho. 

Farmers'  Co-Operative  Canal. 

The  Farmers'  Co-operative  Canal  diverts  water  from 
the  north  side  of  the  Boise  Eiver  just  above  Caldwell,  the 
the  headgate  being  located  almost  opposite  that  of  the 
Riverside  Canal.  The  canal  has  a  total  length  of  about  28 
miles  and  irrigates  bench  lands  entirely.  The  soil  under 
this  canal  varies  from  a  clay  loam  to  a  loose  granite  sand. 

Farmers'  Union  Canal. 

The  Farmers'  Union  Canal  diverts  water  from  the  north 
side  of  Boise  River  near  the  Soldiers'  Home,  a  short  dis 
tance  below  Boise.  The  soil  under  this  canal  is  mostly 
volcanic  ash  or  clay  loam,  there  being  a  small  percentage 
of  somewhat  sandy  soil.  This  canal  is  approximately  20 
miles  in  length  and  irrigates  approximately  7,000  acres  of 
land. 

Settlers'  Canal. 

The  Settlers'  Canal  diverts  its  water  from  the  south  side 
of  Boise  River  within  the  city  limits  of  Boise  and  irrigates 
approximately  12,000  acres  of  clay  loam  bench  land  in  the 
vicinity  of  Meridian  on  the  south  side  of  Boise  River. 

Boise  Valley  Canal. 

The  Boise  Valley  Canal  diverts  its  water  from  the 
Farmers'  Union  Canal  about  one  mile  below  the  intake  of 
that  canal  and  furnishes  water  for  approximately  2,600 
acres  of  sandy  loam  bottom  lands.  The  ground  water 
under  practically  all  of  this  land  rises  every  summer  and 
averages  from  two  to  four  feet  from  the  surface  during  the 
irrigation  season. 

Pioneer  Canal. 

The  Pioneer  Canal  diverts  water  from  the  north  side  of 
the  Boise  River  about  one  mile  southeast  of  Palmer  Station. 
This  canal  is  only  approximately  three  miles    in     length 
and  furnishes  water  for  approximately     1,265     acres    of 
sandy  loam  Boise  bottom  lands.     The  land  under  this  pro 
ject  is  fairly  well  irrigated  during  the   irrigation   season 
by  sub-irrigation  from  the  rise  of  ground  water. 
Eureka  Canal. 

The  Eureka  Canal  diverts  water  from  the  south  side  of 


REPORT  OF  STATE  ENGINEER.  113 

Boise  River  immediately  below  the  headgate  of  the  Phyllis 
Canal.  This  canal  supplies  water  for  approximately  2,000 
acres  of  Boise  bottom  land  and  is  very  similar  in  every 
respect  to  the  Pioneer  Canal. 

Randall  Canal. 

This  canal  diverts  its  water  from  the  Burgess  Canal 
7  miles  southwest  from  Rigby  in  the  upper  Snake  River 
Valley.  It  is  about  five  and  one-half  miles  in  length  and 
furnishes  water  for  approximately  4,000  acres.  The  lands 
under  the  canal  have  a  uniform  topography  and  the  soil 
is  of  a  very  porous,  gravelly  nature,  common  to  30,000  or 
40,000  acres  in  that  vicinity. 

Clark  and  Edwards  Canal. 

The  Clark  and  Edwards  Canal  diverts  water  from  the 
"Big  Feeder"  about  six  miles  southeast  from  Rigby.  This 
canal  is  approximately  four  miles  in  length  and  furnishes 
water  for  about  4,000  acres  of  very  gravelly  land. 

South  Side  Twin  Falls  Canal. 

This  well  known  canal  diverts  water  from  the  south 
side  of  Snake  River  at  Milner  through  a  main  canal  with 
a  capacity  of  3,200  cubic  feet  per  second,  and  25  miles 
long.  The  main  canal  branches  into  two  main  branches 
at  the  end  of  the  25  mile  section,  each  branch  being  ap- 
proximately 35  milesi  in  length.  The  South  Side  Twin 
Falls  Project  consists  of  approximately  200,000  acres  of 
slightly  rolling  clay  loam  or  lava  ash  soil  situated  on  the 
south  bank  of  Snake  River  and  east  of  Salmon  River.  The 
project  has  a  rather  uniform  topography  with  a  slope 
averaging  50  feet  per  mile  to  the  northwest.  The  soil 
varies  in  depth  from  2  to  40  feet  with  a  probable  average 
of  6  to  10  feet,  being  underlaid  with  lava  rock,  there  being 
no  intervening  stratum  of  gravel  or  other  porous  material. 
The  first  irrigation  water  was  applied  to  this  project  dur- 
ing the  seasons  of  1905  and  190f>,  tho  following  tables 
shov-ino-  the  amount  cultivated  during  the  seasons  of  1912 
and  1913. 


114 


REPORT   OP   STATE   ENGINEER. 


Table  Showing  Comparative  Area  Devoted  to  Different  Crops,  of  Areas 
Actually  Irrigated  Under  Ten  Different  Canals. 


Name  of  canal 

rt 

V 
(H 

Hay 

Pasture 

Grain 

Orchard* 

Total 
acres 

7425.50 
6898.50 

12435.25 
13062.41 

6842.70 
7144  42 

11819.80 
11755.00 

2225.49 

2287.00 

2062.00 

1126.54 
1W8.74 

3255.00 
1362.50 

147309.00 
149311.00 

Acres 

I! 

Acres 

<£s 

Acres 

l! 

Acres 

«! 

&H    0 

Riverside                        .... 

1911 
1912 

1911 
1912 

1911 
1912 

1911 
1912 

1911 
1912 

1911 

1911 
1912 

1912 
1912 

1912 
1913 

4059.00 
3455.75 

5526.75 
4890.00 

3339.44 
3045.35 

4385.25 
4490.25 

332.25 

267.00 

369.00 

115.25 
132.50 

1193.50 
570.00 

59229.00 
54903.00 

54.7 
50.1 

44.4 
37.4 

48.8 
42.6 

37.1 
38.2 

14.9 
11.7 

17.9 

10.2 
11.5 

36.6 
41.9 

40.2 
36.8 

175.25 
627.25 

1626.00 
2289.50 

1171.94 
1534.74 

2157.25 
1848.20 

1189.09 
1222.50 

1138.75 

667.67 
689.32 

207.50' 
97.00 

10094.00 
12212.00 

2.4 
9.1 

13.1 
17.5 

17.1 
21.5 

18.2 
15.7 

53.4 
53.4 

55.2 

59.3 
60.0 

6.4 
7.1 

6.8 

8.2 

911.00 
1360.00 

2043.50 
2354.25 

1526.94 
173.7.00 

3686.50 
3294.75 

277.80 
336.0 

505.00 

197.90 
166.75 

1145.00 
463.50 

56379.00 
60805.00 

12.2 
19.7 

16.4 
18.0 

22.3 
24.3 

31.2 

28.0 

12.5 
14.7 

24.5 

17.6 
14.5 

35.2 
34.0 

38.3 
40.7 

2280.25 
1455.50 

3239.00 
3528.66 

804.38 
827.33 

1590.80 
2121.80 

426.35 
461.50 

49.25 

145.72 
160.17 

709.00 
232.00 

21607.00 
21391.00 

30.7 
21.1 

26.1 
27.1 

11.8 
11.6 

13.5 
18.1 

19.2 
20.2 

2.4 

12.9 
14.0 

21.8 
17.0 

14.7 
14.3 

Riverside    

Farmers'   Co-operative.. 
Farmers'    Co-operative.. 

Farmers'     Union         .... 

Farmers'     Union  

Settlers'                  

Settlers' 

Boise    Valley 

Boise   Valley  

Pioneer  

Randall  

Clark  and  Edwards  

South    Side    Twin    Falls 
South    Side    Twin    Falls 

Total  

150303.29 

38947.96 

.... 

137189.89 

•^  4 

61029.71 

.... 

387470.85 

Average    per    cent 

?S  S 

10  1 

15.7 

100.00 

*  Includes  small  fruit,  garden,  potatoes,  and  home  grounds. 


REPORT  OF  STATE  ENGINEER. 


115 


Table  Showing  Acre  Feet  Diverted  Per  Acre  Irrigated  Each  Month 
of  Irrigation  Season  for  Ten  Different  Canals. 


Name  of  canal 

i 

fH 

Acre-feet  diverted  per  acre  irrigated 

13 

£ 

April 

>> 
a 

i 

a 
>-» 

j>> 

c 
1-1 

bi. 

a 
< 

a 
1 

Oct. 

1-15 

16  30 

1-15 

16-31 

Riverside  *, 

1911 
1912 

1911 
1912 

1911 
1912 

1911 
1912 

1911 
1912 

1911 

1911 
1912 

1912 
1912 

1912 
1913 

0.08 
0.11 

0.04 
0.00 

0.14 
0.25 

0.04 
0.00 

0.14 
0.00 

0.00 

0.11 
0.14 

0.00 
0.00 

0.10 
0.09 

0.43 
0.63 

0.38 
0.08 

0.48 
0.68 

0.16 
0.01 

0.27 
0.00 

0.05 

0.40 
0.00 

0.00 
0.00 

0.14 
0.11 

1 
1.40 
1.74 

1.31 
1.07 

1.25 
1.32 

0.42 
0.49 

0.63 

0.46 

0.38 

0.91 
1.12 

0.00 
0.31 

0.60 
0.83 

0.84 

1.46 
1.98 

1.36 
1.26 

1.41 
1.23 

0.72 
0.69 

0.59 

0.50 

0.33 

0.97 
1.62 

1.58 
2.59 

1.10 
1.12 

1.21 

1.54 
1.99 

l.lb 
0.94 

1.25 

1.07 

0.71 
0.70 

0.64 

0.68 

0.34 

1.09 
1.03 

2.25 
3.00 

1.23 
1.25 

0.79 
1.19 

0.44 
0.58 

0.55 
0.53 

0.46 
0.54 

0.42 
0.38 

0.35 

1.01 
0.98 

1.99 
2.67 

1.13 
1.21 

0.79 
1.23 

0.36 
0.56 

0.45 
0.45 

0.42 
0.34 

0.30 
0.37 

0.34 

0.83 

0.82 

0.81 
2.04 

0.61 
0.73 

0.50 
0.62 

0.28 
0.17 

0.13 

0.00 

0.11 
0.10 

0.12 
0.00 

0.03 

0.12 
0.31 

0.25 
0.34 

0.22 
0.20 

0.15 
0.00 

0.19 
0.10 

0.00 
0.00 

0.00 
0.00 

0.00 
0.00 

0.02 

0.00 
0.00 

0.00 
0.00 

0.16 
0.17 

0.05 

7.14 
9.49 

5.52 
4.76 

5.66 
5.53 

3.04 

2.87 

3.11 
2.39 

1.84 

5.44 
6.02 

6.88 
10.95 

5.29 
5.71 

Riverside  * 

Farmers'    Co-operative... 
Farmers'    Co-operative... 

Farmers'   Union  

Farmers'   Union  . 

Settlers'     . 

Settlers' 

Boise    Valley  
Boise    Valley  

Kureka                

Pioneer  

Pioneer  

Randall  , 

Clark   and   Edwards  

South    Side    Twin    Falls. 
South    Side   Twin    Falls. 

Average    for    month... 

.... 

0.08 

0.22 

1.23 

0.89    0.67    0.20 
j 

5.39 

Per  Cent  of  Season's 
Diversion    

1.49 

4.08115.60 
1 

22.43 

22.83   16.5 

12.43 

3.71 

0.93 

100.00 

The  Boise  Valley  canals  included  in  the  foregoing  in- 
vestigation are  fairly  well  distributed  throughout  the 
valley,  supply  water  to  a  large  percentage  of  its  irrigated 
area,  and  there  is  no  doubt  but  that  the  tables  represent 
the  present  average  use  of  water  in  the  Boise  Valley.  The 
Clark  &  Edwards  and  the  Randall  Canals  lie  in  the  upper 
Snake  River  Valley  but  are  not  typical  of  the  majority 
of  the  canals  in  that  district,  for  the  soil  under  them  is 
more  gravelly  than  the  district  as  a  whole  averages.  These 
canals  and  the  use  of  water  under  them,  however,  are  typi- 
cal of  those  supplying  water  for  some  40,000  or  50,000 
acres  in  the  vicinity  of  Rigby.  The  use  of  water  under 
the  South  Side  Twin  Palls  Canal  is  probably  typical  of 
the  majority  of  Idaho's  largest  irrigation  projects,  par- 
ticularly of  those  which  have  a  large  and  adequate  water 
supply. 


116  REPORT  OF  STATE  ENGINEER. 

It  is  regretted  that  the  data  secured  do  not  throw 
any  light  on  the  losses  that  have  been  experienced  by  seep 
age  under  the  projects  investigated.  The  study  of  the  data 
included  in  the  tables  makes  it  quite  evident  that  this 
factor  is  much  greater  than  is  usually  believed.  From  a 
study  of  the  seepage  measurements  which  are  described 
later  in  this  report  it  would  seem  that  the  transmission 
losses  of  Idaho  canals  range  from  20  per  cent  to  as  high 
as  50  per  cent  of  the  water  diverted. 

The  water  supply  in  the  Boise  River  is  usually  plentiful 
for  all  canals  until  the  middle  of  July,  after  which  time 
a  reduction  in  the  amounts  diverted  is  made  by  the  water 
master  on  all  except  those  having  the  earliest  priorities. 
For  this  reason  the  amounts  shown  as  having  been  di- 
verted by  the  Boise  Valley  canals  during  August,  1911. 
are  unquestionably  from  20  to  30  per  cent  below  the 
amounts  needed.  The  flow*  of  the  Boise  River,  however, 
was  above  normal  during  August,  1912,  and  it  is  believed 
that  the  canals  during  that  month  diverted  nil  of  the 
water  that  was  actually  required.  A  comparison  of  the 
above  tables  of  canal  diversions  with  the  preceding  curve 
and  Duty  tables  strikingly  emphasize  many  interesting 
factors: 

(1)  That  where  water  supply  is  plentiful  the  average 
canal  diverts  more  water  than  is  needed  for  economical 
irrigation,  both  at  the  beginning  and  end  of  the  irrigation 
season. 

(2)  That  practically  the  entire  need  for  water  falls 
during  the  four  months  from  May  to  August,  inclusive. 

(3)  That  the  actual  diversion  of  average  canals  is  far 
greater  than  many  have  realized,  indicating  that  the  loss 
from  seepage,  evaporation,  general  waste  and  careless  use 
as  well  as  the  amount  required  for  stock  and  domestic 
purposes  is  far  ereater  in  actual  practice  than  has  usually 
been  acknowledged.     A  careful  study  of  the  above  data 
taking  into  consideration  the  fact  that  the  canals  investi- 
gated represent  an  average  or  a  little  better  than  average 
use  of  water,  makes  it  evident  that  there  is  ^rave  danger 
of  allotting   insufficient   water   to   many   of   our   future 
projects. 


REPORT  OF  STATE  ENGINEER. 

AMOUNT  OF  WATER  USED  ON  TYPICAL  FARMS  UN- 
DER THE  RIDENBAUGH  CANAL  IN  THE  BOISE 
VALLEY  DURING  THE  SEASON  OF  1912. 

It  is  believed  that  the  average  results  of,  the  Duty  of 
Water  Investigation  with  its  variation  of  water  on  ail 
tracts  will  give  the  correct  Duty,  but  as  only  approximate- 
ly one-third  of  the  tracts  involved  have  been  handled  ex- 
clusively by  the  owners  themselves  it  is  realized  that  the 
results  that  have  been  secured  may  not  furnish  an  accu- 
rate idea  of  the  average  use  of  water  in  the  State  at 
this  time.  In  order  to  show  the  average  use  of  water  in  a 
typical  district  and  to  furnish  data  to  strengthen  the  other 
more  exact  Duty  of  Water  experiments  where  the  water 
had  been  varied  and  measured  very  carefully,  it  was  de- 
cided to  detail  one  assistant  during  the  irrigation  season 
of  1912  to  the  measurement  of  the  water  used  by  the 
farmers  on  as  many  farms  as  possible  in  a  typical  district. 

The  district  selected  was  that  lying  under  the  Kiden- 
baugh  Canal  within  a  radius  of  four  miles  of  Meridian. 
Care  was  used  to  include  as  many  as  possible  of  the  staple 
crops  on  the  average  farms  of  the  district,  and  as  much 
was  included  as  one  man  could  cover,  reading  all  weirs  in 
the  supply  ditches  twice  daily.  The  waste  water  was  not 
measured,  but  all  of  the  areas  were  surveyed  very  care- 
fully. There  were  no  restrictions  whatever  placed  upon 
the  users,  and  it  is  believed  that  the  customary  amount 
of  water  was  used,  and  that  an  average  crop  was  produced. 
The  data  secured  are  given  in  the  following  table: 


118 


REPOET  OF   STATE   ENGINEER. 


Fable  Showing-  Amount  of  Water  Used  on  Typical  Farms  Under  the  Ridenbaug-h 
a  Boise  Valley  Canal— During-  the  Season  of  1912. 


Crop 


Remarks 


1  Alfalfa 

2  Alfalfa. 
3|Alfalfa 
4 1  Alfalfa. 
5|Alfalfa 
til  Alfalfa 
7 1  Alfalfa 
8|Alfalfa 
9  Alfalfa 


Alfalfa 

Alfalfa 

2IAlfalfa 

3 1  Alfalfa 


4  Oats 

5  Oats 

6  Oats 

7  Oats 

8  Oats 


3.50 
5.31 
7.06 

26.25 
6.78 
7.68 

10.32 
7.24 
5.85 
3.85 
1.42 
2.65 

15.67 

30.33 
19.32 
33.70 
27.96 

14.58 


5-14—  9-18 
5-13_  8-29  109 


5-15—  9-2 
5-16—  9-8 
5_21_  9-9 
5-18—  9-14 


5-26—  9-15  113 


91  Oats   and 

0| Wheat  

I 

l| Wheat  

2|  Wheat  

i 

SlWinter  Wheat 


Wheat.  11.90 

.52 


10. 


11.24 


l|Clover 
5 1  Clover 


3|Timothy    

7|Orchard    Grass 


3|Pasture     

DJPasture     

3i  Pasture     

L|Pasture     * 

I 

21  Apple  Orchard  . . 
3| Apple  Orchard  .. 
tj Apple  Orchard  .. 

51  Apple  Orchard    .. 

5|  Wheat  and  barley 

I 


5-21—  8-: 
5-16—  8-20 
5-18—  9-25 
5-19—  7-11 
5-20—  8-25 
5-16—  9-21 


128  10  5.6619 
.3961 
.2617 
3747| 
.7999 
.0183 

3.0995 
.7191 
.1101 

2.2104 


120 


(i  :j. 
(i  a. 
t>3. 
63. 
64. 
73! 
52. 

:;:j. 


34.1 


I 
6-17—  7-181  32 


6-12—  7-28 
6-23—  7-28 
6-26—  7-17 
6-26—  8-10 

6-8  —  7-26 
6-20—  8-5 


6-5  —  7-28|  54 
7.4  _  7-171  14 

5-30—  6-4 

5-16—  9-25  133 
5-18—  9- 


5.15—  9-20  129 
5-10—  9-23  137 


5-11—10-1 
5-8  _  9-25 


141 


5-12—  9-12  124 

5.9  _  9-26|141 

I 
7-6  —  8-29|  55 


6-22—  9-7 
7-8  —  9-5 

7-6  —  9-1 
5-29—  7-19 


.3187 
.4656 


21. 


,0445  55.00  bu. 
3  1.7293  53.67  bu. 

1.0853  51.93  bu. 
2  0.8763  32.19  bu. 

1.0869  40.81  bu. 


3572  44.00  bu. 
1993  17.92  bu. 

8864  44.00  bu. 
7586  18.00  bu. 


3567 
6594 


5761 
9250 


144  10  2.6943 
8111 

2770 


73. 

65. 


5.92  tons 
4.67  tons 
4.67  tons 
3.19  tons 
3.63  tons 
3.63  tons 
3.58  tons 
3.25  tons 
3.42  tons 
3.00  tons 
3.25  tons 
1.92  tons 
3.05  tons 


Two   cuttings. 

Two  cuttings,   carelessly  irrigated. 


10.618522.42  bu. 


2.57  tons 
5.74  tons 


2.74  tons 
2.18  tons 


9  3 

1 

3  1.5505  217.  94  bxs. 
30. 


.4493 

.3365 
.5505 
.7081 

.4310 
0.8969  36.95  bu. 


Poor  land  and  poorly  cared  for. 
Very  much  neglected. 


Poor  stand. 
Two  crops. 

One    crop    (yield    baled). 
One  cutting. 

Blue   grass   and  white  clover. 
Blue   grass   and   white   clover. 

Three  years  old. 
One-half  bearing. 
Clean  cultivated,  2  and  3  years  ol< 

Clean   cultivated,    2  and  3  years  ol( 


It  is  realized  that  the  data,  secured  and  tabulated  in  the 
above  tables  are  less  accurate  than  those  of  the  major  in- 
vestigation, but  in  view  of  the  comparatively  large  area 
involved,  the  fact  that  one  man  gave  his  entire  time  to 
the  investigation  during  the  season  and  that  this  man  had 
the  entire  co-operation  of  all  of  the  owners,  it  is  believed 
that  the  data,  secured  are  accurate  enough  for  all  practical 
purposes,  and  that  they  will  furnish  a  clear  idea  of  the 


REPORT  OF  STATE  ENGINEER. 

average  use  of  water  in  a  typical  irrigated  section  of  Idaho. 
There  was  no  U.  S.  Weather  Bureau  Station  located  at 
Meridian,  but  the  precipitation  that  occurred  from  April 
to  September,  inclusive,  was  without  a  doubt  approximate- 
ly the  same  as  that  of  Boise,  which  is  only  9  miles  away. 
This  was  8.25  inches. 

It  is  believed  that  irrigation  is  as  highly  developed,  and 
that  water  is  of  as  much  value,  in  this  locality  as  it  is  in 
any  other  representative  district  of  the  same  area  in  the 
State.  It  is  also  believed  that  the  farmers  use  the  water  as 
carefully  and  waste  as  little  as  they  do  in  any  other  dis- 
trict of  the  same  magnitude.  The  average  of  the  amounts 
used  by  all  of  these  irrigators  was  2.56  acre  feet  per  acre, 
the  water  having  been  measured  in  each  case  within  a 
short  distance  of  the  boundaries  of  the  farms  in  question. 
The  above  use  of  water  agrees  very  closely  with  the  re- 
quirements shown  by  the  major  investigation,  for  if  21  per 
cent  of  the  amount  delivered  and  applied  was  wasted,  the 
amount  retained  would  have  been  almost  exactly  2  acre 
feet  per  acre.  The  crops  produced  that  season  in  the 
district  under  observation  were  fair  and  normal  in  every 
respect.  It  was  the  belief  of  the  owners  that  they  could 
not  have  well  used  any  less  water,  and  that  if  less  water 
had  been  used  the  yields  would  have  been  materially  re- 
duced. It  is  therefore  believed  that  this  supplementary  in- 
vestigation furnishes  strong  and  added  proof  of  the 
adequacy  of,  and  the  necessity  for,  a  water  right  of  suf- 
ficient size  to  permit  of  the  retention  of  2  acre  feet  per 
acre  upon  clay  loam  soils. 

INVESTIGATION  OF  THE  AVERAGE  USE  OF  WATER 
BY  THE  SETTLERS  OF  THE  SALMON  RIVER 
PROJECT. 

Three  assistants  were  detailed  to  the  Salmon  River 
Project  during  the  season  of  1913,  whose  entire  time  was 
devoted  to  the  measurement  and  variation  of  the  water 
applied  to  12  tracts  of  the  staple  cropsi,  each  of  an  ap- 
proximate area  of  15  acres.  Each  of  these  tracts  was 
divided  into  3  approximately  equal  parts.  The  investiga- 
tion as  above  outlined  was  carried  on  in  order  to  ascertain 
the  best  Duty  for  the  various  crops  on  the  project  as  a 
whole,  for  it  was  believed  that  the  variation  of  the  water 
would  throw  new  light  upon  the  actual  water  requirements 
of  the  soils  and  crops. 


120  REPORT  OF  STATE  ENGINEER. 

In  order  to  supplement  the  experiments  where  the  water 
was  varied  and  determine  the  average  use  of  water  by  the 
Salmon  River  settlers  and  to  throw  as  much  additional 
light  upon  the  proper  Duty  of  Water  as  possible,  one  man 
was  detailed  during  the  same  season  to  the  measurement  of 
the  water  applied  by  the  owners  to  parts  of  12  typical 
ranches  well  scattered  over  the  project.  This  was  done 
with  16  automatic  water  registers,  which  were  installed  on 
weirs  in  the  feed  and  waste  ditches  leading  to  and  from 
each  plot.  These  water  registers  consisted  essentially  of 
an  eight  day  clock  and  a  revolving  cylinder  upon  which  a 
paper  record  sheet  w^as  placed.  The  variation  of  the  height 
of  the  water  flowing  over  the  weir  and  the  movement  of  the 
clock  traced  on  the  record  sheets  an  accurate  and  con- 
tinuous record  of  the  height  of  the  water  flowing  over  the 
weirs,  each  record  lasting  an  entire  week. 

Wherever  a  tract  of  sufficient  area  could  be  picked  out 
so  that  all  of  the  feed  water  applied  to  and  all  of  the 
water  wasted  from  the  tract  could  be  measured  by  two 
water  registers,  this  was  done,  but  in  cases  where  the  area 
involved  was  too  small  to  justify  the  expense,  or  where  the 
water  wasted  from  the  field  in  question  through  2  different 
ditches,  the  waste  from  the  fields  was  not  measured.  With 
one  or  two  exceptions  it  is  believed  that  the  results  se- 
cured show  up  the  average  use  of  water  on  the  Salmon 
River  Project  during  the  season  of  1913.  On  account  of 
the  size  of  the  tracts  involved  and  the  wide  area  which 
they  covered  it  was  found  impractical  to  weigh  the  yields 
produced.  These  were  determined  from  the  records  of 
the  automatic  weighers  attached  to  the  threshing  machines 
which  threshed  the  grain,  and  by  measuring  the  alfalfa  in 
the  stack. 

While  the  determinations  of  yields  by  the  above  methods 
were  not  absolutely  accurate,  it  is  believed  they  are  suf- 
ficiently so  for  all  practical  purposes.  All  of  the  areas  in- 
volved were  carefully  surveyed  with  transit  and  chain,  so 
that  part  of  the  following  table  which  shows  depths  ap- 
plied per  acre  is  believed  to  be  very  accurate. 


REPORT  OF  STATE  ENGINEER. 


121 


0        CO  00 


<) 


II  !«  ^ 

S2     1     .     -d 


g- 


£.      co      to 

s,?  °  s 

$1  H  a 


§  §• 

&   3 


g>      0 


a  a 


33 


±       00        C  p  (D  P 

£  £§  s^§- 

»      c?«H       ^« 


|     | 

a  i 


Number 


Showing1 


B; 

<  p 

2  o* 


3  a 

•2.S 

(y    tfj 

a-s 

l>0- 

2  c 

Vt   ^ 

§  a 
o  a 


£ 


G»q 
Q 


Area  —  acres 


Applied 


Wasted 


?£. 


4>.oi      to  to  co 


Depth  in  feet  or 
acre  ft.  per  acre 
applied  to  land 


siss 


2  §r 


&&  o'er 

* 


122  REPORT  OF  STATE  ENGINEER. 

INVESTIGATION  OF  USE  AND  DUTY  OF  WATER 
AND  COST  OF  PUMPING  UNDER  ELECTRICAL 
PUMPING  PLANTS  IN  THE  VICINITY  OF 
WEISER  AND  PAYETTE  DURING  THE  SEASON 
OF  1913. 

Water  is  now  being  pumped  in  Idaho  for  the  irrigation 
of  many  thousands  of  acresi,  but  there  are  still  many  op- 
portunities for  expansion  along  this  line.  This  is  particu- 
larly true  of  the  territory  along  Snake  Eiver  from  Hager- 
inan  as  far  down  as  Huntington,  Oregon,  a  distance  of 
nearly  250  miles,  there  being  available  even  at  low  water 
fully  3,000  cubic  feet  per  second  of  unappropriated  water 
in  this  section  of  Snake  River.  This  water  cannot  be  di- 
verted by  gravity  on  account  of  the  comparatively  high 
banks  and  flat  grade  of  the  river,  but  there  is  considerable 
good  land  adjacent  to  the  river  upon  which  this  water 
might  be,  and  is  being  pumped  with  lifts,  varying  be- 
tween 50  and  200  feet.  The  lands  adjacent  to  Snake  River, 
however,  are  not  all  of  those  upon  which  pumping  may 
be  found  feasible,  for  the  best  land  in  many  projects  lies 
immediately  above  the  high  line  canals,  where  in  many  in- 
stances rather  large  acreages  could  be  covered  with  com- 
paratively small  lifts.  Idaho  has  great  water  powrer  re- 
sources, only  a  small  part  of  which  have  been  as  yet  de- 
veloped, and  considering  this  fact,  and  the  availability  of 
land  and  water,  it  appears  as  though  this  were  a  most  fa- 
vorable field  for  irrigation  pumping. 

The  entire  Duty  of  Water  investigation,  up  until  1913, 
had  been  carried  on  under  gravity  canals  where  there  was 
no  particular  incentive  to  save  water,  and  it  seemed  as 
though  the  time  were  opportune  to  conduct  two  investiga- 
tions in  one  by  determining  (1)  the  Use  and  Duty  of  Water 
under  a  number  of  pumping  plants  where  there  was  a 
strong  underlying  incentive  to  secure  the  highest  possible 
Duty,  and  (2)  to  determine  the  costs  of  pumping  at  the 
same  time.  There  were  163  different  electrically  driven  ir- 
rigation pumping  plants  being  operated  during  the  season 
of  1913  in  the  territory  adjacent  to  the  Snake  River  be- 
t\veen  Caldwell  and  Huntington,  and  it  was  decided  to  as- 
sign one  assistant  to  this  territory  who  should  be  furnished 
with  a  motorcycle  and  who  would  determine  by  means  of 
weirs,  water  registers  and  watt  meters  the  amount  of  water 
pumped  and  electricity  used,  under  as  many  as  possible  of 
the  smaller  or  medium  sized  pumping  plants  in  that  vicin- 


REPORT  OF  STATE  ENGINEER. 

ity.  After  looking  over  the  territory  a  number  of  owners 
and  operators  were  interested  in  the  investigation  and 
some  20  plants  in  the  vicinity  of  Payette  and  Weiser,  Idaho, 
and  Ontario,  Oregon,  were  selected  for  the  season's  test. 
Some  of  the  plants  selected  were  paying  for  their  power  by 
the  meter  rate,  and  some  were  paying  a  flat  rate  based  on 
the  horsepower  of  their  motors.  The  flat  rate  plants  did 
not  all  have  meters  and  it  was  not  possible  to  determine 
the  exact  amount  of  current  consumed  by  them,  but  the 
cost  of  the  service  to  the  farmers  for  the  season,  however, 
based  on  the  amount  paid  to  the  power  company,  was 
easily  determined,  and  the  following  tables  give  the  re- 
sults that  were  secured.  The  cost  of  pumping,  as  given  in 
these  tables,  includes  only  power  charges,  nothing  having 
been  added  for  depreciation,  attendants,  etc. 


124 


REPORT  OF  STATE  ENGINEER. 


1OOJ    3J3B 

—  jooj  jaj 


;ooj  ajDB 


+  -f  + 


ifc 

S&      f, 
r*          i-H 


+  + 

a  £  s  * 


rorr 


"      + 


r       r»      r       10      r- 


8    2 


$888338888883? 


o     o 
-e    -a 


rt     J§ 


£    a 

0         3 

•<       0- 


9JIDB  J8J 


?    8 
58    S 


38    Pi 


otal  No.hrs 
May  to  Sept. 
inc.,  3,672 


UOS139S 

jo  ^naD  aaj 


+  +  + 
^J  i^  ^ 
S  2  J^5 


UOSB9S  J3UI 

-anp  paj-eaado 
sanoq 


Ov      t      r^      _ 
3      I      ft      » 

rr  r-t 


§  s  g 


I  S84DV 


*    8    8    9 

iri      g      i^       •* 
C*      rO      •*•      IH 


jaaj—  jjj 


I       « 

5     H 


S     1 

C5     W 


O        O 
O        O 

2 


lO.uod  aSJOH 


s   §    ;    ; 

a     8     c      : 

Ills 

ll 

bo    C 

3  .         j> 

<     <     O 


«     -H 


3       •- 


REPORT  OF  STATE  ENGINEER.  125 

The  investigation  as  a  whole  showed  up  many  interest- 
ing factors  in  connection  with  the  pumping  of  water  for 
irrigation  purposes,  principal  among  which  are: 

(1)  That  greater  care  should  be  used  in  the  designing 
and  installation  of  the  small  plants  so  as  to  reduce  the 
friction  of  shafts  and  belts,  of  water  in  the  pipes  and  all 
other  losses  to  a  minimum.     Pumps  direct  connected  on 
the  same  shaft  with  the  motor  and  bolted  to  the  same  base 
are  recommended.     Suction  pipes  should  be  as  short  as 
possible  and  intakes  should  be  screened  to  keep  out  all 
trash.    Discharge  pipes  should  contain  as  few  sharp  turns 
as  possible,  and  there  should  be  no  90  degree  angles  in 
them.     These  pipes  should  also  be  of  a  rather  large  bore 
or  diameter  so  as  to  reduce  friction  losses  as  much  as 
possible.     The  inefficiency  of,  and  abnormal  amounts  of 
power  consumed  by  the  small  "stock"  pumps  that  might 
or  might  not  have  been  running  at  the  speed  or  pumping 
against  the  head  for  which  they  were  best  designed,  was 
strikingly    emphasized.      The    design    of    hydraulic    ma- 
chinery, and  particularly  centrifugal  pumps,  is  a  compli- 
cated problem  at  the  best,  and  the  investigation  as  a  whole, 
as  will  be  seen  from  some  of  the  abnormal  pumping  costs, 
seems  to  emphasize  the  desirability  of  having  all  but  the 
smaller  sizes  of  installation  designed  and  installed  by  a 
.hydraulic  engineer  who  is  known  to  be  competent. 

(2)  It  is  not  possible,  generally  speaking,  to  opera  re 
pumping  plants  continuously.     It  should,  however,  be  pos- 
sible to  operate  a  small,  well  designed  plant  at  least  75 
per  cent  of  the  time  during  the  season.    With  the  present 
power  rates  it  is  not  economical  for  the  consumer  to  own 
a  plant  any  larger  than  would  be  required  to  pump  the 
necessary  water  by  operating  three- fourths  of  the  time. 

(3)  The  charges  for  power  that  were  paid  by  the  con 
sumers  for  the  small  or  average  size  pumping  plants  for 
a  five  months'  season   was   $28.00  per  horse-power    for 
plants  up  to  20  horse-power;  $26.00  per  horse-power  for 
plants  from  20  to  40  horse-power;  $25.00  per  horse-power 
for  plants  from  40  to  75  horse-power.    Tho  above  was  the 
flat  rate  charge  per  horse-power.    The  other  class  of  con- 
tract was  a  combination  of  the  meter  and  flat  rate  as 
follows :    f  10.00  per  horse-power  service  charge  for  a  five 
months'  season,  plus  two  cents   (2c)    per  kilowatt  hour 


126  REPORT  OF  STATE  ENGINEER. 

for  all  current  consumed  with  a  $20.00  per  horse- power 
minimum  charge  for  the  season. 

The  results  of  the  investigation  seem  to  indicate  that 
the  development  of  new  lands  in  Idaho  at  the  present  time 
will  not  withstand  the  charges  necessary  when  water  is 
raised  over  150  feet,  and  not  over  100  feet  would  be  recom- 
mended in  many  cases  except  with  the  larger  installations 
where  a  much  higher  efficiency  can  be  secured.  The  abovo 
seems  true  in  most  cases  for  lifts  above  100  feet,  for  the 
annual  maintenance,  which  includes  (a)  expense  of  at- 
tendants, including  ditch  riders;  (b)  repairs  and  general 
depreciation  of  plant;  (c)  interest  on  original  cost;  (d) 
charges  for  power,  lubricating  oil,  etc.,  will  be  too  excessive 
for  the  development  of  raw  land  except  in  exceptional 
cases.  Old  bearing  orchards,  vineyards  and  other  highly 
remunerative  crops  will  necessarily  withstand  greater 
power  charges  and  consequent  greater  lifts  than  the  de- 
velopment of  raw  land.  It  must  be  borne  in  mind  that  the 
man  under  the  pumping  plant  with  his  high  annual  main 
tenance  charge  must  in  almost  all  cases  compete  with  his 
neighbor  under  a  gravity  canal  with  a  consequent  lesser 
charge  for  annual  maintenance. 

The  results  of  the  investigation  as  a  whole  were  quite 
satisfactory,  but  owing  to  the  flat  rate  power  charges  and 
the  $20.00  minimum  clause  in  the  meter  rate  contracts,  it 
was  found  that  there  was  no  more  incentive  to  save  water* 
than  under  some  of  the  gravity  canals.  Some  of  the  users 
were  particularly  wasteful  of  their  water.  This  was  very 
disappointing,  but  in  all  probability  added  time  will  give 
both  the  farmers  and  the  power  company  experience  that 
will  tend  to  better  the  conditions  that  now  exist.  The 
major  factor  brought  out  by  the  investigation  was  the  de- 
sirability of  better  designed  and  installed  equipment. 
This  will  be  imperative  in  order  to  make  a  permanent  suc- 
cess of  irrigation  pumping. 

Subsequent  mechanical  efficiency  tests  showed  that  the 
over  all  efficiencies  of  the  plants  in  the  Pavette  district 
ranged  from  less  than  25  per  cent  to  as  much  as  75  per 
cent.  The  majority  of  the  plants  included  in  the  1913  in- 
vestigation above  outlined  were  developing  efficiencies  of 
loss  than  40  to  45  per  cent,  showing  that  the  farmers  were 
pa.yinc:  nearly  twice  as  much  power  charges  as  should 
have  been  necessary  for  the  amount  of  water  pumped.  The 


REPORT  OF  STATE  ENGINEER.  127 

fault,  however,  was  invariably  in  the  poor  design  and 
faulty  installation  of  the  plants,  rather  than  with  the  rate 
paid  for  power.  The  farmer  must  be  made  to  realize  that 
the  best  designed  plant  of  the  best  possible  construction  is 
by  far  the  cheapest  in  the  end,  though  the  initial  cost  may 
be  50  per  cent  greater  than  some  plants  might  be  installed 
for. 

AMOUNT  OF  WASTE  OR  UNIRRIGATED  LAND  IN  A 
TYPICAL  PROJECT. 

The  total  amount  of  water  required  by  any  project,  as 
has  been  outlined  previously  in  this  report,  depends  upon 
at  least  four  factors:  (1)  the  Duty  of  Water  at  the  land; 
(2)  the  amount  of  transmission  loss  between  the  point  of 
diversion  and  the  land  to  be  irrigated;  (3)  the  amount  of 
loss  from  reservoirs;  aud  (4)  the  proportion  of  a  project 
that  is  ultimately  irrigated.  The  above  factors  must  all 
be  given  serious  consideration  when  designing  any  irriga- 
tion project,  aud  as  far  as  all  practical  purposes  are  con- 
cerned, are  of  equal  importance,  for  to  err  or  miscalculate 
in  regard  to  any  one  of  them  might  in  some  cases  be  the 
cause  of  the  failure  of  the  project. 

The  fourth  factor,  the  proportion  of  a  project  that  is 
ultimately  irrigated,  is  considered  to  be  fully  as  vital  and 
important  as  any  of  the  others  which  have  a  bearing  upon 
the  amount  of  water  required  for  a  project,  for  it  would 
unquestionably  be  impossible  to  design  any  project  proper- 
ly and  economically  without  a  knowledge  of  this  factor, 
even  though  all  of  the  other  factors  involved  were  accurate- 
ly known.  So  far  as  the  individual  user  is  concerned,  it 
may  be  found  that  the  irrigation  company  will  be  re- 
quired to  deliver  him  water  on  the  basis-  of  the  number  of 
acres  actually  owned  and  upon  which  he  pays  maintenance 
without  regard  to  how  much  of  his  land  is  devoted  to  roads 
and  waste  or  other  uncultivated  area.  Yet  so  far  as  a 
project  as  a  whole  is  concerned,  it  seems  quite  evident  that 
the  total  amount  of  waste  and  unirrigated  land  in  the 
project  will  always  be  a  dominant  factor,  for  even  though 
the  individual  is  delivered  water  on  a  basis  of  the  area 
actually  owned,  water  will  not  be  used  on  the  waste  places, 
and  the  water  for  the  balance  of  the  project  will  be  ma- 
terially increased  thereby. 

It  has  been  roughly  estimated  by  many  engineers  in  the 
past,  there  having  been  no  accurate  data  in  regard  to  the 


128  REPORT  OF  STATE  ENGINEER. 

subject,  that  20  per  cent  of  a  normal  project  would  always 
be  unirrigated  from  a  variety  of  causes.  The  author  has 
always  believed  this  estimate  to  be  too  high  for  Idaho 
projects,  for  wherever  large  bodies  of  high  land  or  rough, 
rocky  land  have  existed  they  have  been  eliminated  from  the 
project  at  the  outset.  It  has  not  seemed  possible  that  the 
ordinary  waste  or  unirrigated  area,  consisting  of  county 
roads,  railroad  rights  of  way,  ditch  rights  of  way,  fence 
rows,  corrals,  stack  yards,  small  high  spots  and  other 
wasites  of  all  kinds  has  amounted  in  any  one  year  on  a 
well  developed  project  to  as  much  as  20  per  cent  of  the 
total  area  for  Avhich  water  rights  were  provided.  Realizing 
the  extreme  importance  of  this  factor  and  the  utter  lack  of 
dependable  data  in  regard  to  it,  it  was  decided  some  two 
years  ago  that  this  factor  should  be  determined  for  Idaho 
conditions.  It  was  decided  that  the  determination  should 
be  made  by  means  of  an  actual  survey  of  typical  irrigated 
land,  in  contiguous  bodiesi  located  in  at  least  two  different 
typical  Idaho  irrigation  projects. 

After  considering  several  projects  and  looking  over  a 
large  amount  of  land,  two  localities  were  selected  as  being 
typical  of  Idaho's  irrigation  projects.  One  of  these  was 
in  the  Boise  Valley  in  the  vicinity  of  Meridian,  where  land 
had  been  farmed  for  fifteen  or  more  years,  and  the  other 
was  in  the  heart  of  the  South  Side  Twin  Falls  Project,  in 
the  vicinity  of  and  surrounding  the  town  of  Kimberly,  five 
miles  east  of  Twin  Falls.  Twenty  sections  were  surveyed 
in  a  contiguous  body  lying  immediately  north  of  and  adja- 
cent to  the  town  of  Meridian,  and  skirting  the  Boise  Valley 
bottom  lands  on  the  south.  The  land  surveyed  was  ail 
bench  land  and  was  typical  in  every  respect  of  the  better 
class  of  irrigated  land  in  the  Boise  Valley.  THie  other  area 
surveyed  consisted  of  six  sections  entirely  surrounding,  but 
one-fourth  of  a  mile  removed,  from  the  Kimberly  townsite. 
This  land  was  typical  in  every  respect  of  the  better  class  of 
irrigated  land  on  the  South  Side  Twin  Falls  Project.  Land 
immediately  adjoining  the  towns  was  not  included  in  the 
investigation,  for  it  was  divided  into  such  small  holdings 
that  it  was  considered  not  typical  of  a  project  as  a  whole. 
Sections  were  frequently  encountered  during  the  survey 
that  seemed  to  vary  somewhat  from  the  typical  on  account 
of  too  much  or  too  little  waste  land,  but  as  the  specific  area 
to  be  surveyed  had  been  predetermined  as  typical  these 
areas  were  always  included  along  with  the  rest  so  as  to 


REPORT  OF  STATE  ENGINEER.  129 

eliminate  the  personal  equation  of  the  men  who  did  the 
actual  field  work. 

These  surveys  were  made  with  the  transit  and  chain.  The 
notes  were  platted  on  detail  paper  to  a  scale  of  200  feet  to 
the  inch  and  the  areas  were  determined  with  a  polar  plani- 
meter.  A  reasonable  amount  of  care  was  always  used,  and 
while  it  is  known  that  the  areas  included  in  the  table  are 
not  exactly  accurate,  there  is  no  doubt  but  that  they  are 
accurate  enough  for  all  practical  purposes. 

The  total  areas  devoted  to  each  of  the  various  irrigated 
crops1  and  the  total  areas  devoted  to  the  various  non-irri- 
gated areas  were  segregated  and  are  shown  in  the  table 
which  follows.  As  most  of  the  surveys  were  made  during 
the  fall  and  spring,  or  non-irrigation  season,  it  has  not  been 
possible  to  determine  the  exact  amount  of  land  that  was 
unused  or  fallow  for  a  variety  of  reasons,  and  there  is  no 
column  set  aside  for  this  class  of  land  in  the  table.  The 
field  men  who  made  the  survey  insist  that  there  was  none, 
and  that  whatever  fallow  land  that  existed  in  the  entire 
area  was  still  devoted  to  sage  brush  that  could  and  would 
be  cultivated  and  irrigated  at  no  distant  date. 

It  is  believed  that  the  total  area  surveyed,  consisting  of 
1 6,065.21  acres,  is  large  enough  so  that  a  dependable  esti- 
mate for  similar  projects  may  be  based  upon  it,  for  the  total 
area,  considered  is  in  itself  as  large  as  some  irrigation 
projects,  and  is  one-quarter  or  one-half  as1  large  as  the  ma- 
jority of  them  in  the  West  today.  It  is  realized  that  there 
is  always  a  small  amount  of  fallow  land  in  any  project  that 
may  be  uncultivated  for  a  year  or  two  for  a  variety  of  rea- 
sons, such  as  sickness  or  death  of  the  owner,  failure  to  find 
a  renter,  trouble  over  water  rights,  or  ditch  rights1  of  way, 
or  the  breaking  of  ditches.  While  it  is  realized  that  such 
fallow  land  will  always  exist  in  all  projects,  it  is  believed 
that  the  per  cent  devoted  to  it  will  necessarily  be  very 
small  in  a  typical  highly-developed  South  Idaho  project, 
and  that  it  will  never  exceed  over  1  or  2  per  cent  of  the 
total  area,  where  the  project  is  well  developed,  which  in- 
tensive development  must  take  place  if  the  project  is  to  be 
a  success.  For  those  who  have  use  for  the  data  contained 
in  the  table,  it  is  suggested  that  not  over  1  to  2^  per  cent 
should  be  added  for  fallow  land  to  the  waste  or  non-irri- 
gated acreage  shown.  The  addition  of  a  percentage  for 
fallow  land  to  the  percentage  shown  in  the  table  should  give 
the  total  waste  or  non-irrigated  area  of  the  project. 


130  REPORT  OF   STATE   ENGINEER. 

Space  will  not  permit  of  even  a  brief  description  of  each 
of  the  sections  that  have  been  surveyed,  and  the  readers 
must  assume  that  they  consist  of  typical,  well  irrigated 
land,  planted  to  diversified  crops.  A  study  of  the  detailed 
table,  however,  should  furnish  considerable  information  in 
regard  to  each  section.  The  20  sections  in  the  vicinity  of 
Meridian  consisted  of  holdings  of  various  sizes,  these  hold- 
ings ranging  from  4  to  19  different  farms  per  section.  The 
average  for  the  entire  area  surveyed  was  10.65  farms  per 
section. 


3    I 


REP  OUT   OF   STATE  ENGINEER. 

:BSS£taSSgaStig«oo-ao»o,,*MwM       Number 


131 


HHM.~HHOOClbob°5°E 

:JLF&  WJSH.HH.H 


coco  b  en  btabtNa^Jbo  bb^oabsbo  witooobicbscobbof-' 


M  M  M  -1  CO  -»  M  l-i  to  IsS  l-«  tO  CO  M  t*  b»  bO  b*  OO  CO  M  to  IsJ  to 


cw^tOMMOOCT«ooa-^cnososocflts3i>9M«>-Joabacooowcn 


i  *>-cncci>t»- 


a* 

& 

& 

£L£ 


CLP 
P  3 

=ra 
o 


"r* 

3  2 


8  S, 

ST  5»  tn  n      -^ 

" 


v><*$  jj^ 


^ 
« 

3 

r^- 
^ 

S2. 

x* 

C^ 
rb 
o 

O* 
3 


132  REPORT   OF   STATE   ENGINEER. 

Space  will  not  permit  of  including  carefully  prepared 
maps  of  a  sufficiently  large  scale  to  show  up  the  individual 
differences  that  existed  between  the  sections  surveyed,  nor 
of  a  table  of  sufficient  size  to  show  the  acreages  of  all 
classes  of  crop  that  existed  in  each  individual  section.  The 
above  table  gives  the  results  secured  from  the  survey  in  a 
rather  condensed  form,  which,  it  is  believed,  will  be  de- 
tailed enough  for  all  practical  purposes.  In  working  up 
the  data,  each  class  of  crop  or  class  of  waste  land  was 
totaled  separately.  Of  the  area  surveyed,  which  consisted 
of  16,065.21  acres,  4,417.22  acres,  or  27.5  per  cent,  were  de- 
voted to  hay;  grain,  4,327.56  acres,  or  26.94  per  cent; 
pasture,  2,447.58  acres,  or  15.24  per  cent ;  potatoes,  137.19 
acres,  or  0.85  per  cent;  orchard,  2,360.4  acres,  or  14.69 
per  cent;  vineyard,  2.76  acres,  or  0.02  per  cent;  corn,  17.26 
acres,  or  0.11  per  cent;  garden,  105.58  acres,  or  0.66  per- 
cent; sugar  beets,  155.25  acres,  or  0.97  per  cent;  clover, 
94.72  acres,  or  0.59  per  cent;  beans,  25.14  acres,  or  0.16  per 
cent;  berries,  3.01  acres,  or  0.02  per  cent;  peas,  198.69 
acres,  or  1.23  per  cent;  sage  brush  which  will  be  irrigated, 
199.62  acres,  or  1.24  per  cent;  home  grounds,  5.03  acres,  or 
0.03  per  cent;  miscellaneous  irrigated  crops,  273.68  acres, 
or  1.7  per  cent,  making  a  total  irrigated  acreage  of  14,- 
770.69  acres,  or  91.94  per  cent.  The  waste  or  non-irrigated 
acreage  consisted  of  corrals,  99.85  acres,  or  0.62  per  cent; 
barn  and  stack  yards,  24.78  acres,  or  0.16  per  cent;  fence 
rows,  87.49  acres,  or  0.55  per  cent;  sloughs,  44.15  acres, 
or  0.28  per  cent;  creeks,  97.33  acres,  or  0.61  per  cent; 
canal  and  ditch  rights  of  way,  229.14  acres,  or  1.43  per 
cent;  county  and  private  road  rights  of  way,  351.19  acres, 
or  2.18  per  cent;  railroad  rights  of  way,  93.38  acres,  or 
0.58  per  cent;  coulees,  93.10  acres,  or  0.57  per  cent;  build- 
ing sites,  139.35  acres,  or  0.86  per  cent;  high  land,  2.67 
acres,  or  0.02  per  cent;  miscellaneous  non-irrigated  areas, 
32.09  acres,  or  0.2  per  cent,  making  a  total  non-irrigated 
acreage  of  1,294.52  acres,  or  8.06  per  cent,  the  total  area 
surveyed  consisting  of  16,065.21  acres.  The  reader  will  bear 
in  mind  when  consulting  this  table  that  all  lands  to  which 
water  was  not  applied,  except  uncleared  land  which  could 
and  will  be  irrigated,  is  listed  under  waste  land.  Consider- 
ing the  investigation  as  a  whole  from  the  detailed  data 
which  are  given  ir^  the  table,  it  would  seem  as  though 
none  of  Idaho's  normal  projects  would  ultimately  have 


REPORT   OF   STATE   ENGINEER.  138 

over  10  per  cent  of  waste  or  non-irrigated  land  contained 
in  them,  provided  the  size  of  the  projects  is  based  on  the 
number  of  acres  sold  and  for  which  maintenance  is  an- 
nually paid.  The  data  therefore  seem  to  prove  conclusive- 
ly that  where  it  is  desired  to  irrigate  100,000  acres,  an 
ample  and  dependable  water  supply  for  at  least  90,000 
instead  of  only  80,000  should  be  secured. 

SEEPAGE  INVESTIGATION. 

There  has  always  been  a  serious  lack  of  dependable  data 
concerning  the  transmission  losses  of  Idaho  canals.     It 
seems  to  have  been  customary  when  designing  Idaho  pro- 
jects to  allow/  for  a  loss  of  one  per  cent  per  mile,  based  upon 
the  amount  carried  at  the  upper  end  of  each  one-mile  sec- 
tion. This  estimate  has  been  made  rather  arbitrarily  and 
without  much  data  to  back  it  up,  but  on  the  whole  has  given 
fairly  good  results  when  normal  soil  conditions  have  been 
encountered.    Idealizing  that  irrigation  water  was  becom- 
ing more  valuable  each  year  and  that  projects  were  being 
continually  based  on  narrower  margins  it  became  apparent 
that  the  transmission  loss  to!  which  a  project  would  be 
subject  was  an  extremely  vital  factor.     It  was  felt  that 
this  factor  was  fully  as  important  as  the  Duty  of  Water 
at  the  land  or  the  percentage  of  the  project  that  is  ulti- 
mately irrigated,  and  it  was  decided  to  broaden  the  Duty 
of  Water  investigation  by  determining  the  seepage  losses 
on  a  sufficient  number  of  canals  so  that  a  stable  basis  for 
further  estimates  of  these  losses  might  be  secured.    It  was 
known  that  the  type  of  material  through  which  a  canal 
was  built  had  an  important  bearing  on  the  subject,  and 
it  was  hoped  through  investigation  to  determine  an  aver- 
age loss  for  the  different  soil   types  and  thus  establish 
a  safe  basis  to  work  from  in  the  future.    An  investigation 
of  the  subject  was  initiated  in  the  spring  of  1912  and 
carried  on  uninterruptedly  throughout  that  and  the  follow- 
ing irrigation  season,  during  which  time  seepage  losses 
were  determined  on  118  sections  of  different  canals  with 
a,  total  length  of  nearly  300  miles. 
Canal  Losses. 

Canals  are  subject  to  three  different  kinds  of  transmis- 
sion losses.  These  are  leakage,  evaporation  and  seepage. 
The  losses  from  leakage  are  usually  caused  by  cheap  and 


134  REPORT  OF  STATE  ENGINEER. 

improper  construction  or  wornout  structures,  and  should 
be  practically  negligible  with  an  efficient,  well-designed 
and  carefully  maintained  canal. 

The  evaporation  losses  from  canals  are  usually  so  small 
as  to  be  almost  negligible.  Careful  mathematical  deter- 
minations of  this  factor  show  that  the  evaporation  losses 
from  typical  Idaho  canals  usually  amount  to  not  over  one 
per  cent  of  the  total  lossi  to  which  water  is  subject  in 
transmitting  it  from  the  point  of  diversion  to  the  point  of 
application  to  the  land,  99  per  cent  is  usually  due  to  seep- 
age and  only  1  per  cent  to  evaporation  from  the  water  sur- 
face. 

That  the  above  is  true  may  be  roughly  determined  very 
easily  by  any  one.  The  evaporation  from  a  free  water 
surface  in  evaporation  tanks  installed  for  the  purpose  at 
different  points  well  scattered  throughout  irrigated  South 
Idaho  averages  about  1.5  inches  per  week  throughout  the 
irrigation  season,  and  has  never  been  known  either  at  Twin 
Falls,  Caldwell  or  Gooding,  to  exceed  over  2.3  inches  in 
any  one  week.  A  typical  canal  with  a  water  surface  I 
rod  wide  would  have  2  acres  of  surface  exposed  per  mile. 
A  normal  capacity  for  a  canal  of  this  width  would  be  at 
least  125  cubic  feet  per  second.  A  normal  loss  for  ihis 
canal  would  be  1  per  cent  per  mile,  or  1.25  second  feet, 
which  would  be  equivalent  to  2.5  acre  feet  per  day,  or  17.5 
acre  feet  per  week,  whereas  the  evaporation  loss  from  this 
same  canal  with  its  exposed  surface  of  2  acres  could  not 
average  over  3  acre  inches,  or  one-quarter  of  an  acre  foot 
per  week.  This  evaporation  loss,  which  is  the  highesc  that 
could  possibly  take  place  from  the  surface  of  the  cool 
water  in  the  canal,  would  thus  in  the  above  case  ainouut 
to  only  one-seventieth  of  the  total  amount  lost  by  the  canal 
from  both  seepage  and  evaporation.  The  striking  compari- 
son that  exists  between  the  evaporation  and  the  seepage 
losses  that  are  experienced  from  typical  canals  was  well 
brought  out  in  the  last  biennial  report  of  the  Idaho  State 
Engineer's  office,  and  the  above  discussion  is  included  here 
to  further  emphasize  the  very  small  losses  that  ordinary 
canals  experience  through  evaporation  from  their  exposed 
surface.  Since  the  losses  from  leakage  and  evaporation 
are  so  insignificant  in  comparison  to  those  experienced 
from  seepage  the  losses  in  this  report  vvili  all  be  classed 
as  seepage  losses. 


REPORT   OF   STATE   ENGINEER.  135 

Units  Used  to  Express  Seepage  Losses. 

It  has  long  been  customary  to  express  the  seepage  losses 
as  per  cent  of  the  total  flow  lost  per  mile  of  canal,  based 
on  the  flow  at  the  upper  end  of  each  1-mile  section.  This, 
however,  is  a  very  misleading  and  unsatisfactory  method 
of  expressing  these  losses,  for  they  are  not  only  largely  in- 
dependent of  the  amount  of  water  flowing  in  the  canal, 
but  the  loss  when  expressed  in  per  cent  per  mile  shows 
an  abnormal  increase  in  canals  of  small  capacity.*  It  will 
be  seen  that  a  canal  carrying  only  a  small  per  cent  of 
its  capacity  will  lose  an  abnormally  large  per  cent  per  mile, 
while  if  the  losses  are  expressed  as  so  much  per  unit  of 
wetted  area  they  are  bound  to  be  less  misleading  and  will 
compare  favorably  with  the  losses  experienced  when  tht 
canal  is  full. 

While  there  are  many  factors  which  influence  and  affect 
the  amount  of  loss  by  seepage,  the  loss  is  unquestionably 
a  function  of  the  wetted  perimeter  and  must  be  expressed 
in  terms  of  quantity  lost  per  unit  of  wetted  area  if  com- 
parable results  between  different  canals  are  to  be  obtain- 
ed. For  this  reason  all  losses  in  this  report  are  expressed 
as  "cubic  feet  lost  per  twenty-four  hours  for  each  square? 
foot  of  wetted  area  in  the  canal  bed"  as  well  as  in  "per  cent 
of  loss  per  mile." 

Method  of  Measurement. 

Ditches  or  laterals  carrying  three  second  feet  or  less 
were  measured  with  Cippoletti  weirs  which  were  carefully 
installed  at  the  upper  and  lower  ends  of  each  section.  The 
head  on  these  weirs  was  read  to  the  nearest  .001  of  a  foot 
with  small,  inexpensive  hook  gages  which  were  designed 
especially  for  the  purpose.  All  of  the  larger  laterals  and 
canals  were  measured  by  current  meters.  Where  conven- 
ient bridges  could  be  found  from  wflrich  to  make  measure- 
ments these  were  used,  but  wading  measurements  were 
found  necessary  on  some  of  the  broad  shallow  canals  carry- 
ing only  a  small  per  cent  of  their  capacity.  The  measure- 
ments of  the  South  Side  Twin  Falls  Main  and  High  Line 
Canals  were  made  from  a  boat  especially  fitted  up  for  the 
purpose.  This  boat  was  attached  to  cables  stretched 
across  the  canal  in  much  the  same  manner  as  a  small  ferry 

*See  Bulletin  No.  126,  U.  S.  Department  of  Agriculture,  by  Samuel 
Fortier. 


136  REPORT  OF  STATE  ENGINEER. 

boat.  The  North  Side  Twin  Falls,  the  second  largest 
canal  included  in  the  investigation,  was  rated  from  a  car 
suspended  on  cables  which  were  installed  above  and  across 
the  canal  at  appropriate  places.  The  meters  used  in  the 
work  were  the  standard  Gurley  Price  weight  meters. 
These  meters  were  all  rated  at  the  beginning  of  the  1912 
season,  one  new  one  having  been  rated  by  the  Bureau  of 
Standards  at  Washington,  D.  C.,  and  the  others  at  the 
rating  station  of  Irrigation  Investigations  at  Berkeley, 
California.  The  1912  rating  was  used  for  all  1912  deter- 
minations, and  all  meters  were  again  rated  at  the  rating 
station  of  Irrigation  Investigations  at  Berkeley,  Califor- 
nia, at  the  close  of  the  season  of  1913.  Most  of  them 
showed  a  remarkable  agreement  with  the  1912  rating,  only 
one  being  off  far  enough  to  vitiate  the  results  obtained. 
The  1913  measurements  made  with  this  meter  were 
changed  in  accordance  with  the  rating  curve  made  up  for 
it  in  the  fall  of  1913. 

The  .2,  .6  and  .8  or  three-point  method  of  measurement 
was  used  in  all  cases  where  the  water  exceeded  a  depth  of 
one  foot,  and  either  the  .6  or  integration  method  with  shal- 
lower ditches.  In  computing  the  discharges  the  following 
formula  was  used : 

( Vel.  at  .2)+ (2*  Vel.  at  .6)-f  (Vel.  at  .8) 

-.  equals  uav  ge  velocity 

The  fluctuations  of  gage  height  or  intermittent  rise  and 
fall  of  the  water  has  been  the  most  troublesome  factor 
with  which  hydrographers  have  had  to  contend  in  the 
making  of  seepage  measurements  in  the  past,  and  it  was 
decided  to  eliminate  this  factor  as  nearly  as  possible  so 
that  it  could  have  no  appreciable  effect  on  the  results  se- 
cured in  this  investigation.  It  is  believed  that  this  was 
thoroughly  accomplished,  and  as  the  method  used  was 
more  or  less  original  and  has  not  been  seen  in  print  else- 
where, it  will  be  given  here  with  the  hope  that  it  might  lxj 
of  assistance  to  other  engineers  and  hydrographers  who 
may  be  called  upon  to  make  accurate  determinations  of  the 
seepage  losses  from  canals. 

The  canals  included  in  the  investigation,  and  upon 
which  seepage  losses  were  to  be  determined,  were  looked 
over  and  examined  quite  thoroughly  before  any  measure- 
ments were  made.  Rating  stations  were  picked  out  and 
established  at  the  head  of  all  diversions  and  at  intervals 


REPORT  OF  STATE  ENGINEER.  137 

of  as  near  two  miles  apart  in  the  main  canal  as  sections 
suitable  for  the  purpose  could  be  found.  Gages  which 
could  be  read  to  the  nearest  .02  of  a  foot  were  then  install- 
ed at  each  station,  after  which  the  canal  was  rated  at  each 
station  by  at  least  two  hydrographers,  each  with  a  differ- 
ent meter,  in  order  to  avoid  not  only  error  in  computation, 
but  to  eliminate  the  personal  equation  of  the  man,  and  any 
slight  discrepancies  in  the  meters.  Kating  curves  were 
then  plotted  for  each  section  measured  using  the  bottom 
of  the  canal  as  the  zero  point  on  the  curve  and  the  point 
at  which  water  stood  when  the  ratings  were  made  for  the 
only  other  point  which  was  determined  on  each  curve.  The 
water  level  in  the  canal  was  maintained  throughout  and 
for  some  time  after  the  measurement  as  nearly  constant  as 
it  could  be,  there  being  usually  less  than  .05  of  a  foot  fluc- 
tuation in  the  water  level  during  the  period  covered  by  the 
investigation.  After  all  of  the  stations  selected  had  been 
rated  by  the  two  men,  measurements  were  discontinued  for 
a  day  and  floats  consisting  of  tightly  corked  bottles  or  tin 
cans  were  dropped  into  the  main  canal  at  the  upper  gage 
and  allowed  to  float  downward  with  the  current.  These 
floats  were  started  at  daylight,  a  man  proceeding  down 
with  them  and  reading  each  gage  in  the  main  canal  and 
in  all  of  the  diversions  at  the  time  that  the  floats  passed 
the  gage  in  question.  More  floats  and  another  man  fol- 
lowed the  first  ones  at  2  or  3  hour  intervals  throughout 
the  entire  day  and  the  discharge  at  and  consequent  seep- 
age losses  between  each  two  different  points  was  calculated 
from  the  discharge  based  on  the  rating  curves  and  gage 
heights  at  the  time  that  the  floats  passed  the  different 
stations. 

Determinations  by  the  above  method  compare  discharges 
of  practically  the  same  flow  or  wave  of  water  at  the  time 
it  passed  different  points,  and  is  believed  to  be  far  more 
accurate  than  any  simultaneous  measurements.  While 
the  floats  did  not  necessarily  proceed  down  the  canals  at 
exactly  the  same  rate  as  the  average  velocity  of  the  ditch, 
and  while  the  rating  curves,  each  of  which  were  based  on 
but  two  points,  may  not  have  been  absolutely  accurate,  the 
canals  were  held  as  uniform  as  possible,  and  as  there  was 
biit  slight  fluctuation  in  any  case  between  the  time  of  the 
original  rating  and  the  time  the  floats  passed  the  gages  it 
is  believed  that  the  discharges  secured  from  the  curves  are 


138  REPORT  OF  STATE  ENGINEER. 

quite  accurate  and  that  the  results,  secured  as  above  out- 
lined, have  eliminated  personal  equations  of  men,  individ- 
ual characteristics  of  meters,  and  slight  fluctuations  of 
canals  and  are  more  accurate  on  the  whole  and  better  than 
any  other  method  that  has  yet  been  devised.  The  table 
which  follows  the  descriptions  given  below  gives  the  aver- 
age seepage  loss  for  a  12  or  14  hour  period  of  the  different 
sections  of  each  canal  that  have  been  investigated.  It  is 
regretted  that  space  will  permit  of  only  a  very  brief  de- 
scription of  the  canals  included  in  the  investigation.  They 
are  all  more  or  less  typical  of  the  ordinary  canals  in  use 
throughout  the  West  and  it  is  hoped  that  the  following 
brief  description  will  furnish  sufficient  data  to  give  a  fair- 
ly accurate  idea  of  the  different  sections  included  in  the 
investigation. 

The  numbers  of  the  following  paragraphs  correspond 
with  the  numbers  of  the  different  sections  in  the  seepage 
table,  and  are  arranged  in  practically  the  same  order. 

1  to  21  inclusive.  Typical  small  farm  laterals  located 
on  the  South  Side  Twin  Falls  Project,  Salmon  River 
Project  and  the  Ridenbaugh  Canal  in  the  Boise  Valley. 
The  majority  of  the  soils  through  which  these  laterals 
were  constructed  consisted  of  the  medium  clay  k»am  or 
lava  ash  common  to  South  Idaho.  The  n^ajority  of  these 
soils  were  underlaid  with  calcareous  hard  pan  at  depths 
ranging  from  one  and  one-half  to  four  feet.  Some  of  these 
laterals  had  rather  swift  velocities,  erosion  having  takeo 
place  down  to  the  hard  pan. 

22.  This  section  was  located  five  and  one-half  miles 
southwest  of  Rigby  in  the  Upper  Snake  River  Valley  and 
was  constructed  through  a  gravelly  sandy  loam  soil. 

23.  A  typical  farm  lateral  on  the  South  Side  Twin 
Falls  Project. 

24.  A  lateral  of  the  Salmon  River  Project  near  Am- 
sterdam.   The  abnormal  amount  of  seepage  from  this  lat< 
eral  was  caused   by  the  shallow  soil   through   which   it 
was  constructed,  there  having  been  a  large  amount  of 
shale  incorporated  into  its  banks. 

25  to  28  inclusive.  Typical  laterals  on  the  South  Side 
Twin  Falls  and  Salmon  River  Projects. 

29.  Typical  lateral  on  the  Portneuf  Marsh  Valley 
Project  near  Downey. 


REPOET  OP  STATE  ENGINEER.  139 

30  to  33  inclusive.  Typical  laterals  of  the  Oakley 
Project. 

34  and  35.  Laterals  near  Rigby;  constructed  through 
very  gravelly  soil. 

36  and  37.    Laterals  near  Hollister.    Clay  loam  soil. 

38  to  40  inclusive.    Laterals  of  the  Oakley  Project. 

41.  Lateral    near    Rigby;  constructed    through    very 
gravelly  soil. 

42.  Typical  lateral,  Salmon  River  Project. 

43  to  45  inclusive.    Typical  laterals,  Oakley  Project. 

46.  Lateral  of  the  Burgess    Canal  near  Kigby;  con- 
structed through  a  medium  gravelly  soil. 

47.  Typical  lateral  of  Portneuf  Marsh  Valley  Project 
mear  Downey. 

48  to  51  inclusive.  Typical  laterals  of  North  Side  Twin 
Falls,  South  Side  Twin  Falls  and  Oakley  Projects.  Sec- 
tion 50  showed  a  gain  occasioned  by  porous  irrigated  land 
above  the  canal. 

52.  Lateral  of  Burgess  Canal  near  Rigby;  constructed 
through  gravelly  soil. 

53.  Typical  lateral  of  South  Side  Twin  Falls  Project. 
54  and  55.    Main  Canal  of  Murphy  Land  &  Irrigation 

Co.,  constructed  through  medium  clay  loam  soil,  section 
55  containing  a  few  somewhat  gravelly  side  hill  sections. 

56.  Extension  of  East  Side  Main  Canal,  Oakley  Project; 
constructed  through  heavy  clay  loam  soil  slightly  mixed 
with  sand;  heavy  grade  with  consequent  swift  velocity. 

57.  Lateral  of  Twin  Falls  North  Side  Project  rear 
Wendell. 

58.  Lateral    C,    Portneuf    Marsh    Valley    Irrigation 
Project,  2  miles  north  of  Downey. 

59.  Portion  of  Main  Canal,  Twin  Falls  Salmon  River 
Project. 

60.  Portion  of  Vance  Canal  four  and  one-half  miles 
southwest  of  Rigby.     Soil  very  gravelly. 

61.  Section  of  Main  Canal  of  the  Twin  Falls  Salmon 
River   Project,    commonly   known   as    "Main   2V    Canal, 
carrying  only  a  small  per  cent  of  its  capacity. 

62  to  64  inclusive.  Parts  of  Main  Canal,  Portueuf 
Marsh  Valley  Project. 

65.  West  Main  Canal,  Oakley  Project.  First  season 
of  use;  was  constructed  around  a  very  gravelly  hillside; 


140  BBPOKT  OF  STATE  ENGINEER. 

Lower  bank  showed  much  gravel  but  contained  sufficient 
percentage  of  clay  to  render  it  comparatively  impervious. 

66  and  68.    Main  Canal,  Portneuf  Marsh  Valley  Project. 

67.  Lateral  21  of  Salmon  River  Project.  Bather  shal- 
low clay  loam  soil  with  banks  solid  and  compact. 

69.  Typical  lateral  of  South  Side  Twin  Falls  Project. 

70.  Portion  of  Main  (Janal  of  Salmon  River  Project 
near  Hollister,    carrying   only   a   small   per   cent   of   its 
capacity. 

71.  West  Main  Canal,  Oakley  Project.    Canal  was  con- 
structed through  a  gravelly  side  hill  formation  which  had 
n  sufficient  amount  of  clay  mixed  with  it  to  render  it  com- 
paratively impervious. 

72  and  74.  Typical  laterals  of  South  Side  Twin  Falls 
Project. 

73.  Lateral  A  of  Salmon  River  Project,  carrying  only 
a  small  per  cent  of  its  capacity. 

75,  83,  87,  89,  98,  and  100.  Main  Canal  of  Pioneer  Irri- 
gation District  in  the  Boise  Valley.  Section  75  of  this 
canal  was  located  between  Caldwell  and  Nampa  and 
traversed  a  territory  where  ground  water  was  very  close 
to  the  surface.  The  gain  in  this  section  was  due  to  the 
proximity  of  the  ground  Avater.  The  remainder  of  this 
canal  was  fairly  typical  of  Idaho  canals,  having  been  con- 
structed almost  entirely  through  a  clay  loam  soil  of  a  me- 
dium nature. 

76  and  77.    East  Side  Main  Canal,  Oakley  Project. 

78  and  79.  Portions  of  Main  Canal,  Twin  Falls  Salmon 
River  Project. 

80.  Randall  Canal  near  Rigby;  constructed  through 
gravelly  soil. 

81  and  82.  Main  Canal  of  Deitrich  segregation,  Idaho 
Irrigation  Company's  Project  near  Richfield.  Section  81 
was  constructed  in  the  main  through  clay  loam  s^il  but 
contained  several  rock  cuts. 

84.  Consisted  of  the  entire  length  of  Perrine  Coulee, 
the  well-known  lateral  on  the  South  Side  Twin  Fails 
Project.  This  coulee  was  measured  during  the  month  of 
July,  1913,  at  the  height  of  the  irrigation  season.  Measure- 
ment of  this  coulee  was,  made  at  this  time  to  determine 
whether  or  not  well  defined  coulees  picked  up  enough 
waste  water  from  the  adjacent  farms  to  more  than  offset 


REPORT  OF  STATE  ENGINEER.  141 

their  seepage  losses.  Extreme  care  was  used  in  the  Meas- 
urement of  this  coulee  and  it  was  found  that  the  waste 
water  which  was  picked  up  hardly  equaled  or  offset  the 
loss  in  the  coulee  by  seepage,  the  net  loss  being  .1  of  cne 
per  cent  per  mile.  The  section  of  the  coulee  was  so  irregu- 
lar that  there  was  no  attempt  made  to  base  the  seepage 
losses  on  the  amount  of  wetted  area  in  the  coulee. 

85  and  86.  Portions  of  Main  Canal,  Twin  Falls^almon 
River  Project.  Section  86,  first  section  below  lIR^Jieck 
basin,  listed  as  99  and  101. 

88  and  90  to  95  inclusive.  Farmers'  Co-operative  Canal 
in  the  Payette  Valley  near  Emmett.  Tt  had  been  thought 
by  some  that  this  canal  had  abnormal  losses  and  that 
the  seepage  conditions  in  the  valley  were  largely  due  to 
the  losses  from  this  canal.  The  losses  from  the  canal,  as  will 
be  seen  from  the  table,  were  rather  low.  One  section, 
where  ground  water  was  near  the  surface  in  the  surround- 
ing soil,  showd  a  gain.  The  measurements  as  a  whole 
clearly  indicate  that  the  seepage  conditions  in  the  Payette 
Valley  are  not  caused  by  the  seepage  losses  from  this 
canal.  Soil,  a  clay  loam  and  sandy  loam. 

99  and  101.  The  check  basin  in  the  Main  Canal  of  the 
Salmon  Eiver  Project.  These  two  sections  represent  meas- 
urements of  this  check  basin  during  the  different  years.  Re- 
sults represented  by  No.  99  were  secured  during  the  season 
of  1912,  and  those  represented  by  No.  101  were  secured 
during  July  of  1913.  This  check  basin  is  simply  an  en- 
largement of  the  canal  or  a  pot  hole  which  is  used  MS 
part  of  the  canal  section  to  eliminate  the  necessity  of  con- 
structing a  canal  around  it.  The  check  basin  covers  about 
62  acres  when  full.  The  soil  in  the  bottom  of  the  basin 
is  a  clay  loam  varying  in  depth  from  one  to  two  feet,  under 
laid  by  lava  rock.  The  measurements  clearly  indicate  that 
it  would  be  wise  to  construct  a  canal  around  this  depres- 
sion. 

102  to  106  inclusive.  Include  the  High  Line  Canal  of  the 
South  Side  Twin  Falls  Project  from  the  point  where  it 
leaves  the  Main  Canal  to  Cottonwood  Flumo  south  of  Kim- 
berly.  This  canal  shows  a  gain  in  two  different  sections. 
Section  No.  102  is  that  portion  which  crosses  McMnllin 
Creek,  and  section  104  is  that  portion  which  crosses  Rock 
Creek,  there  being  porous  irrigated  land  lying  above  each 


142  REPORT  OF  STATE  ENGINEER. 

one  of  these  sections.  The  gain  clearly  indicates  that  the 
canal  in  these  sections  is  picking  np  from  sub-surface 
sources  some  of  the  underground  water  from  the  porous 
irrigated  land  above. 

107  to  112  inclusive.  Represents  results  secured  from 
different  sections  of  the  Main  Canal  of  the  North  Side 
Twin  Falls  Project  from  Milner  to  Jerome  Reservoir.  The 
Upper  end  of  Section  112  is  located  at  the  Milner  Dam, 
and  the  lower  end  of  Section  107  includes  part  of  Jerome 
Reservoir.  Part  of  Section  112  is  lined  with  concrete. 
Section  111  includes  Wilson  Lake  Reservoir. 

113  to  118  inclusive.  Includes  the  Main  Canal  of  the 
Twin  Falls  South  Side  Project  from  Milner  to  the  point 
approximately  25  miles  below  where  the  Main  Canal  di- 
vides into  the  High  and  Low  Line  Canals.  Section  1.16 
includes  Dry  Creek  Reservoir  only.  This  reservoir  is 
formed  where  the  main  canal  crosses  Dry  Creek,  where 
the  canal  simply  consists  of  a  lower  bank,  the  water  back- 
ing np  Dry  Creek  far  enough  so  that  it  forms  a  lake  cov- 
ering 965  acres.  The  embankment  is  approximately  one 
mile  long  and  35  feet  high.  No.  118  is  that  portion  of  the 
canal  extending  from  the  wagon  bridge  near  Milner  and 
immediately  below  the  dam  to  a  point  3.35  miles  below. 
There  are  several  rock  cuts  throughout  this  section,  it  be- 
ing the  only  section  where  an  abnormal  loss  occurred.  The 
losses  in  all  other  sections  were  practically  normal,  yet  tho 
canal  lost  over  500  cubic  feet  per  second  throughout  the 
section  observed,  which  was  less  than  25  miles  in  length. 
When  considered  from  the  standpoint  of  the  total  amount 
of  loss  alone,  leaving  out  of  consideration  the  percentage, 
this  loss  is  thorouprhlv  enormous. 

The  South  Side  Twin  Falls  Canal  is  constructed  princi- 
pally through  a  clay  loam  soil  of  a  rather  impervious  na- 
ture and  was  running  very  full  of  water  at  the  time  of  tho 
investigation. 


REPORT   OF   STATE   ENGINEER. 


143 


—  UOT1D9S    H[ 


10 


1391   DUOD9S 

—  HO1JD9S    JO 

pub  jgddn 


UOUD9SSSOJD 


11 


00»COWC«ao^Mi^»^rH05MNt^U5l^lfl»eOOCt^l^«0»OWOCOOU3N05<Mr- 
"   r  "5  CTJ  Cft  OO'  rj  00  CO  OS  U5  N  **'  50  C^  tp  OO  CO  rH  O  *f  CO  t-'  CO  "*'  rH  OO  C«5  U?  <M 


rH       rH       ifl 


J      ans  J9JT2AV 
jo  mpiAV  -AV 


jo 


«^<i^L-L3t^(»ajt^^«Der.^«o«o<w 


i  1l1gfi?gg<2g'gfi1glggg11g?gggg1?1fi!«oooll§ 

SSSSSSSSSSSa><ua)<i>aia)a)4iQ)aja)a>aja>a)ii)<i)   .  a>^ 


144 


REPORT  OF  STATE  ENGINEER. 


Q)  <D 

>  > 

cJ  c3 


o       o 


•  Him  .i.xl 

SSOJ  JU33  J9<J 


sanoq 

•B9JB  P9U9AV 

•}j    bs  J9d 
j   -no 


CO  _ -M  .—       r-l     •  T— CT 

>"5"^"«e^«5"^:^"^"o^^r=^^; 


TOI  J9d  SS01 


JTfOt-CXOOCCXOC^OCOCCT 
'  rH  C<i     '  rH  rH     '  rH     '  M  o'  C<i 


J98J  PU039S 
—  UO1JO9S   Ul 


)COCOif30OOOO5-*e-rH< 


oo  m  co  TH  10 1 


>Oi-tooo'2<=>oS°5?(55£O000' 


I9ai  puonas     looooocoooooc^oooo<omoooo|oooooooo(oocoo< 

pua  J3A\Ol 


J93J  PUOD9S 
— UOIJD9S    |O 

pua  J9ddn 


c-  oo  w'o  os  as  cs  N  c 1  co  eo  t   t»  os  en  OT 


puooas  J9d  ' 


19aj  ajtiubs — 

UOT1D9S  SSOJD 


J  —  'JHS  J91UA1 

jo  qjpiM  -Ay 


199  J — 

jo  qidap  - 


o  •*  c  -fl- 

1 


i-HCCC<l(MC<JC^Cs|C>IC<li— i^"CO 


isssg^^ggg^g; 

*lOt~«MC;OCOOCOrHOOt--< 


oqiftO 

rH  ^  CO 


SBSSSSBSlgS^o;SS3So!^SS5S;SS5gSsa^g5Sfi8gSSaS^ 


mosaic-.    ic«jCiC:'o;<:ri':^c'-;ai:icr-a::;;:x 


oo  (>•  w  oo  oo  o>  CD  «D  «o  ao  oc  ao  ta  i 


-  oo  oo  oo«o  oo 


REPORT   OF   STATE   ENGINEER. 

I    I 


o         o    o 

G       &       G       G 

a     *>     o     o 

fill 


Lf5  IM  r-) 


.     3         « 

C       <D 

"32       ^ 

O     OQ O__      M     O 

o~  o>  i«  o  us  Tt«  ?o  »  IH  TH  oo  o  L»  N  oo  in  < 


C  C  QJ 

'M  "53  K 

cS  cs 

n  PQ  fe 


d          o       ei.c     X  cd      cc          « 

o     y    Oo  uo  o     & 

3~^0»  ®"l>~30~?-r  •  U5      •  (M  »  tXJ  C-000 


145 


I  & 

*  5 


. 

S-        O 

Q    tf 


<M        CMeoONTH        IM 


O        THOOO(NOr-l 


OOlNOrHO     • 


liHOOOO 


10  Tf«M  tr-  US  55  TH 


w  IM      cq  c<» 


>IM  I    THCq         THOlH 


T"     '"'i ; ; ; !  i ; 

fH  O5      •  t— 


«oo M<OOOOOI-K 


C<I        POO3OOO<M        CO  C<l  P3        ?H  O  Tf  iH  O  N  «C>  CvJ  IO  O      •  CQ 


O  OO  < 

TH'CO, 


l  iH  CO  <M  C<I  •*  50  CO  CO  CO  T}<  CO  CO  rH  C«5  IM  IM  (M  IM  M  W  -f  <M      •  IO        <M  IM  (M  N  O3  W  US  OO  (M  OO  Tf  US 


i  7  i  -:   ~.  i  r.   i  -   '-  "i  —  I  -  ->.  i—  I  - 
"7itj3C*-OCO'*J«l>-'*fOOOTttOOC£>< 


»O  1C  O  O5  Utl  ( 


ICq(M(M(M(MTHeOTHTH(M      •  rH  iH  OO  y)  g^(M  <M  Oq  gq  C<l  CN  TH_tH [gj 


cogoeo    -cooo 

goo    .< 


O<OO{OOOi 
l  TH  m  CO  (^  IO  iH  < 


tftt-OOO 


T-HOOOOIM 


tftirs  mus< 


§^!5S^S^S^5gg 


«D  «O  LO -^f  CO  O  OOOOiOUS^f 


_;  :s3js  ;  ;  Xs"  ;  a^^;^::::^;^^:^;-;^: 


'5S5      fi    -dnSO^^os        jr p5C     MH  o  c 

.W^j^^J-i   :SCK       •    .  Sri  <Drir^rir^riri^-2  S   -w'd 


. 


^»^^ia^-|^ri;:;:r^i:-^3233^as*si-H|^ 


2        w  J  v 


Hjlrfrf&Jti'gBB'EloBgB  g  |  e  ifefe 


146  REPORT  OF  STATE  ENGINEER. 

Seepage  determinations  were  made  during  the  seasons  of 
both  1912  and  191.3.  The  results  secured  during  both  sea- 
sons are  included  in  the  above  table.  The  results  of  1913 
served  to  strengthen  but  did  not  materially  change  the 
conclusions  that  had  been  arrived  at  following  the  close  of 
the  1912  investigation.  The  major  factors  brought  out  by 
the  two  seasons'  investigation  are : 

1.  The  great  difference  that  exists  in  the  amounts  lost 
by  canals  constructed  through  different  types  of  soil. 

2.  That  farm  laterals,  carrying  one  second  foot  or  less 
are  subject  to  such  an  abnormal  percentage  of  loss  that  a 
great  waste  takes  place  from  them  when  they  are  used  for 
conducting  water  even  for  short  distances.    This  shows  up 
the  value  of  rotation,   where  the   necessity   of   carrying 
small  amounts  is  eliminated. 

3.  That  certain  types  of  soil  have  a  fairly  uniform  loss 
per  square  foot  of  canal  bed,  and  that  loss  in  per  cent  per 
mile  is  misleading. 

4.  That,  all  other  things  being  equal,  canals  should  be 
designed  with  as  small  a  wetted  perimeter  as  possible  in 
comparison  to  their  cross  section,  or,  in  other  words,  as 
large  a  hydraulic  radius  as  possible,  if  seepage  is  to  be  re- 
duced to  the  minimum. 

5.  That   high  velocities    which    erode    and    scour    the 
banks  increase  seepage  losses. 

6.  That  porous  irrigated  land  above  a  canal  may  cause 
a  srain  instead  of  a  loss. 

7.  That  all  other  things  being  equal,  there  is  less  loss 
where  coulees  or  natural  drainageways  are  used  for  canals 
than  where  constructed  canals  are  used. 

8.  That  a  fill  or  dike  usually  shows  a  greater  loss  than 
a  canal  in  a  normal  section. 

9.  That  canals  in  average  South  Idaho  soil,  which  is  a 
medium  clay  loam,  should  be  designed  to  withstand  a  loss 
of  from  0.5  to  1.5  cubic  feet  per  square  foot  of  canal  bed  per 
twenty-four  hours.    That  0.5  cubic  feet  per  square  foot  per 
day  is  a  safe  basis  for  impervious  clay  soils,  about  1.0  cubic 
foot  per  day  for  medium  soils,  and  from  1.5  to  2.0  cubic 
feet  per  square  foot  per  day  is  a  safe  basis  for  somewhat 
pervious  soils. 

Canals  in  gravel,  depending  upon  the  porosity  of  the 
gravel,  should  be  designed  to  withstand  a  loss  of  from  2.5 
to  5.0  cubic  feet  per  square  foot  of  canal  bed  per  twenty- 


REPORT  OF  STATE  ENGINEER.  147 

four  hours,  though  it  is  probable  that  lining  would  be 
profitable  if  the  higher  loss  were  experienced. 

10.  That  a  project  having  a  comparatively  long  main 
canal  may  lose  as  much  as  30  or  40  per  cent  of  the  water  di- 
verted before  it  reaches  the  farms,  even  in  the  impervious 
soils. 

FACTS  BROUGHT  OUT  DURING  THE  INVESTIGA- 
TION AND  CONCLUSIONS  IN  REGARD  TO 
DUTY  OF  WATER. 

Scope  of  Investigation. 

It  is  believed  that  the  Idaho  Duty  of  Water  investiga- 
tion has  been  the  largest  and  most  comprehensive  investi- 
gation of  the  kind  that  has  ever  been  carried  on.  It  is 
also  believed  that  the  data  secured,  practically  all  of  which 
is  contained  in  this  report,  will  furnish  a  reliable  basis  for 
the  determination  of  the  proper  Duty  for  any  irrigation 
project  where  similar  conditions  obtain.  The  investiga- 
tions upon  which  this  report  is  based  have  covered  four 
seasons,  during  which  time  the  water  used  and  yield  pro- 
duced has  been  accurately  measured  on  529  individual 
tracts,  consisting  of  a  total  area  of  slightly  over  3,600 
acres.  These  tracts  have  included  all  of  the  staple  crops 
and  soils  common  to  South  Idaho.  The  water  diverted  and 
used  by  seven  different  canal  systems  in  1911  and  eight 
different  systems  in  1912  was  measured.  Seepage  losses 
have  been  determined  on  118  different  sections  of  dif- 
ferent canals  with  a  total  lineal  length  of  287.31  miles.  A 
total  area  of  16,065.21  acres,  including  all  or  part  of  26 
typical  sections  has  been  surveyed  for  the  determination  of 
the  waste  or  non-irrigated  acreage.  In  addition  to  the  fore- 
going measurements  and  determinations,  a  large  number  of 
supplementary  investigations  were  made,  among  which 
were  investigations  of  the  "use"  of  water:  (1)  in  the 
Malad  Valley,  (2)  on  the  Salmon  River  Project,  and  (3) 
in  the  Boise  Valley,  and  the  Use  and  Duty  of  Water  and 
cost  of  pumping  under  electrically  driven  pumping  plants 
in  the  vicinity  of  Weiser  and  Payette.  The  covst  of  the  in- 
vestigation for  the  four  seasons  from  its  inception  in  the 
spring  of  1910  up  to  and  including  January  1,  1914,  was 
slightly  over  fifty-five  thousand  ($55,000.00)  dollars. 


148  REPORT  OF   STATE   ENGINEER. 

Factors  Which  Affect  and  Determine  the  Duty  of  Water. 

The  investigation  as  a  whole  has  thrown  much  new  light 
on  the  majority  of  the  many  phases  of  irrigation  practice, 
has  determined  a  proper  Duty  for  the  common  types  of 
soil  and  kinds  of  crop,  and  has  pointed  out  those  factors 
which  have  the  major  effect  or  influence  upon,  and  which 
determine  the  Dutv  of  Water  for  any  project. 

The  factors  which  have  a  direct  bearing  upon,  and  which 
determine  the  Duty,  are:  (1)  Character  of  soil  and  sub- 
soil, (2)  fertility  of  the  soil,  (3)  climatic  conditions,  (4^ 
value  of  water,  (5)  diversification  of  the  farm  crops,  (6) 
use  of  rotation  and  size  of  irrigation  head  used,  (7)  prep 
aration  of  the  land,  (8)  kind  of  crop,  and  other  factors  of 
lesser  importance. 

1.     Character  of  Soil  and  Subsoil. 

The  character  of  the  soil  and  its  porosity  has  more  in- 
fluence upon  the  Duty  of  Water  than  any  other  one  thing. 
The  porosity  of  the  soil  seems  to  be  the  most  important 
factor  and  must  always  be  given  careful  consideration 
when  determining  how  much  water  is  required  for  the  suf 
ficient  irrigation  of  any  soil.  Much  greater  losses  are  be- 
ing experienced  from  deep  percolation  on  irrigated  lands 
than  most  irrigators  realize.  These  losses  have  been  found 
to  be  the  most  frequent  and  serious  source  of  loss  or  waste 
of  irrigation  water  on  all  but  the  most  impervious  of  soils. 
Tf  land  is  underlaid  with  clay  or  with  a  tight  impervious 
hard  pan  there  cannot  be  any  serious  loss  from  this  source, 
but  in  cases  where  soil  is  underlaid  by  a  stratum  of  porous 
sand  or  gravel,  large  losses  are  quite  certain  to  be  experi 
enced.  There  is  no  economical  method  of  irrigation  that 
has  been  yet  devised  that  will  reduce  the  requirements  of 
porous  soils  to  that  of  the  more  impervious  soils.  Porous 
soils  will  therefore  always  require  a  larger  allotment  of 
water  than  the  medium  soils. 

Moisture  moves  through  soils  in  all  directions  by  capil 
larity,  the  downward  movement  being  assisted  by  gravity. 
The  rate  and  extent  of  the  rise  or  movement  of  the  mois- 
ture in  the  soils  depend  principally  upon  the  size  and  ar- 
rangement of  the  soil  particles.  Where  only  a  reasonable 
amount  of  moisture  (4  to  6  inches)  is  forced  into  soils  at 
each  irrigation  the  majority  of  it  usually  rises  again  to  the 
surface  by  capillarity  as  the  surface  gradually  dries  out 


REPORT  OF  STATE  ENGINEER.  149 

The  coarser  the  soil  particles  the  shorter  will  be  the  dis 
tance  the  moisture  can  rise,  hence,  if  a  soil  is  porous  and 
consists  of  rather  large  particles,  greater  losses  are  not 
only  experienced  from  deep  percolation  than  with  the  me- 
dium soils,  but  a  lesser  quantity  of  that  absorbed  by  the 
subsoil  can  be  returned  to  the  surface  layers  by  capillary 
attraction  where  it  can  be  used  by  the  plant  roots.  It  is 
therefore  very  essential,  where  the  highest  possible  Duty 
is  required,  that  soils  be  selected  of  fine  to  medium  and 
practically  uniform  texture  to  a  depth  of  at  least  six  feet, 
for  if  even  a  comparatively  thin  layer  of  coarse  porous 
soil  is  found  underneath  the  surface  it  will  not  only  great- 
ly facilitate  losses  by  deep  percolation,  but  will  effectually 
prevent  the  rise  of  the  water  into  the  surface  layer.  Where 
such  porous  layer  exists  practically  all  of  the  water  that 
penetrates  beyond  it  will  be  lost  to  the  use  of  the  plants  un- 
less the  roots  penetrate  through  it. 

A  tight  impervious  hard  pan  through  which  roots  can 
penetrate,  but  wihich  effectually  cuts  off  percolation  has 
been  found  to  have  a  tendency  to  increase  the  Duty  of 
Water.  Great  losses  are  now  being  experienced  from  deep 
percolation  on  the  gravelly  lands  of  Idaho  because  of  crude 
methods  of  irrigation.  This  has  been  amply  demonstrated 
by  the  "tank  experiment"  on  the  Bate  ranch  near  Idaho 
Falls,  which  is  described  later  in  the  report.  It  has  been 
tehown  conclusively  that  economic  use  of  water  on  these 
porous  lands  can  only  be  secured  by  building  frequent  cross 
ditches  and  using  such  large  heads  of  water  that  the  sur- 
face can  be  flooded  over  so  quickly  that  excessive  loss  from 
deep  percolation  cannot  take  place.  Too  much  emphasis 
cannot  be  placed  upon  the  necessity  and  desirability  of 
using  large  irrigation  heads  on  porous  soils,  for  it  is  utter- 
ly impossible  to  irrigate  them  economically  or  to  avoid 
abnormal  deep  percolation  losses  if  comparatively  small 
irrigation  heads  are  used.  This  emphasizes  the  desirability 
of  rotation  systems  by  means  of  which  large  heads  can  be 
commanded  by  the  farmers  for  comparatively  short  periods. 
The  California  irrigators  are  coping  successfully  with  this 
problem  by  proper  preparation  of  their  land  and  the  use 
of  irrigation  heads  of  as  much  as  from  20  to  30  second  feet. 
These  large  heads  are  used  under  a  strict  rotation  system, 
each  individual,  no  matter  what  the  size  of  his  holdings, 
being  compelled  to  use  this  amount  of  water.  Heads  of 


150  REPORT  OP  STATE  ENGINEER. 

this  size  are  delivered  to  each  user  at  intervals  of  from  21 
to  30  days  throughout  the  irrigation  season,  each  individual 
being  allowed  to  retain  this  head  for  only  20  to  30  minutes 
for  each  acre  upon  which  he  pays  maintenance.  Heads  of 
the  above  size  are  very  common  in  both  the  Sacramento 
and  San  Joaquin  Valleys,  and  are  perfectly  possible  and 
feasible  in  many  parts  of  Idaho,  and  until  Idaho  irrigators 
are  made  to  realize  the  economy  of  both  time  and  water 
that  might  be  secured  by  the  use  of  larger  irrigation  heads 
for  shorter  periods  the  best  results  can  ever  be  obtained. 

Impervious  clay  and  adobe  soils  usually  do  not  absorb 
water  readily  enough,  and  it  is  hard  to  make  them  absorb 
a  sufficient  amount  per  irrigation  to  last  for  any  consider- 
able period.  This  necessitates  more  frequent  irrigation 
on  this  type  of  soil  than  on  the  deep  medium  soils.  There 
is  therefore  no  doubt  that  a  larger  percentage  of  the  water 
applied  to  impervious  soils  is  lost  by  evaporation  than  of 
that  applied  to  the  medium  or  porous  soils.  Losses  by  deep 
percolation,  however,  with  the  more  impervious  soils  are 
impossible,  and  it  has  been  found,  generally  speaking, 
that,  due  to  the  physical  impossibility  of  wasting  water 
by  deep  percolation  on  these  soils,  the  saving  effected  more 
than  offsets  the  extra  evaporation  loss  which  takes  place 
from  them,  and  that  in  general,  less  water  is  required  for 
their  efficient  irrigation  than  .with  any  of  the  porous  or 
mediumly  porous  soils. 

These  shallow  and  impervious  soils,  however,  usually 
absorb  water  so  slowly  and  such  a  small  percentage  of  the 
amount  applied  that  it  is  impossible  to  prevent  an  undue 
amount  of  water  from  running  off  of  the  lands  that  are 
being  irrigated.  This  factor  must  be  taken  into  considera- 
tion when  allotting  water  to  individuals  with  impervious 
or  shallow  soils.  The  extra  amount  of  waste  water  can 
usually  be  caught  up  below  the  farms,  however,  and  meas- 
ured out  to  the  neighbors,  so  that  while  more  water  must 
be  delivered  to  the  individuals,  a  project  as  a  whole  will 
not  require  any  more  water  than  with  the  medium  soils. 
2.  Fertility  of  Soils. 

The  fertility  of  the  soil  has  been  found  to  have  a  great 
influence  on  the  quantity  of  water  required  to  produce  a 
given  crop.  This  has  been  proven  experimentally  by  many 
investigators,*  and  recently  by  the  Washington  and  Ne- 

*  See  U.  S.  Dep.  Agr.,   B.  P.   I.   Bui.  No.   284. 


REPORT  OF  STATE  ENGINEER.  151 

braska  Experiment  Stations,  and  in  a  broader  and  more 
practical  manner  the  same  thing  is  shown  by  the  present 
investigation.  Professor  O.  C.  Thorn,  Soil  Physicist  of  the 
Washington  Agricultural  College,  has  demonstrated  that 
plants  grown  on  sterile  sand  and  irrigated  with  water 
containing  a  strong  solution  of  plant  food  re- 
quired less  than  one-half  as  much  water  per  gram 
of  yield  produced  as  the  same  required  when 
planted  on  the  same  kind  of  sand,  but  when  irrigated  with 
water  containing  a  weak  solution  of  plant  food,  and  that 
the  water  requirements  per  unit  of  yield  slowly  but  grad- 
ually decreased  as  the  strength  of  the  solution  was  in- 
creased. The  Nebraska  Experiment  Station  in  Bulletin 
Xo.  128  shows  conclusively  that  corn  requires  far  less  water 
per  unit  of  yield  on  fertile  soils  than  the  same  crop  re- 
quires when  planted  on  infertile  soils. 

The  Duty  of  Water  Investigation  upon  which  this  re- 
port is  based  has  also  shown  up  this  factor  in  a  very  strik- 
ing manner.  While  no  experiments  were  planned  and  in 
eluded  in  the  Duty  of  Water  Investigation  for  the  specific 
purpose  of  showing  a  comparison  between  the  requirements 
of  fertile  and  infertile  soils,  a  careful  study  of  the  results 
secured  during  the  investigation  clearly  indicates  that 
very  fertile  soils  will  always  produce  more  crop  with  a 
given  amount  of  water  than  the  soils  of  poor  fertility,  and 
that  they  require  less  water  and  frequently  less  than  one 
half  as  much  water  for  the  production  of  the  same  crop  as 
do  the  infertile  soils.  This  fact  is  clearly  shown  in  the 
grain  curve  on  page  100  which  is  given  in  the  early  part 
of  this  report.  Experiments  planned  especially  for  the 
determination  of  this  factor  have  since  been  carried  on  at 
the  Twin  Falls  Experiment  Station  of  Irrigation  Investi- 
gations and  fully  bear  out  the  assertions  that  have  been 
above  made  in  regard  to  the  performance  of  crops  planted 
on  the  more  fertile  soils.  The  influence  of  soil  fertility 
upon  water  requirements  strongly  emphasizes  the  necessity 
of  maintaining  high  fertility  in  all  irrigated  soils,  partic- 
ularly where  economy  of  water  is  a  factor,  and  helps  to 
explain  the  decrease  in  the  requirements  for  water  after 
a  project  has  been  irrigated  a  few  years. 

3.     Climatic  Conditions. 

The  annual  precipitation  and  its  seasonal  distribution, 
together  with  the  temperature,  humidity  and  wind  move- 


REPORT  OF  STATE  ENGINEER. 

ment,  all  have  a  very  marked  and  evident  effect  upon  the 
amount  of  irrigation  water  required  for  crop  production 
on  an  irrigation  project.  The  effects  of  these  factors  are 
so  evident  that  they  will  not  be  discussed  in  detail  in  this 
report. 

The  investigation  has  proven  conclusively,  however,  that 
a  light  summer  rainfall  has  far  less  effect  upon  crop  pro- 
duction that  has  usually  been  believed.  This  is  accounted 
for  by  the  fact  that  the  South  Idaho  atmosphere  is  nor- 
mally very  dry  and  the  light  rains  of  from  one-quarter  to 
one-half  inch  do  not  penetrate  deeply  enough  to  reach  the 
soil  zone  occupied  by  the  plant  roots  and  hence  evaporate 
before  sufficient  time  has  elapsed  for  them  to  be  of  any 
material  benefit  to  the  crops.  In  many  cases  it  has  been 
noted  that  light  rains  have  done  positive  damage  rather 
than  good,  for  they  have  effectually  destroyed  any  soil 
mulch  that  might  have  been  manufactured  to  retain  the 
moisture  which  had  been  applied  to  the  soil  by  previous  ir- 
rigations. The  normal  precipitation  that  occurs  in  Idaho 
during  the  irrigation  season  is  so  light  that  the  variations 
of  the  precipitation  between  the  different  localities  seem  to 
have  practically  no  effect  upon  the  Duty  of  Water.  The  re- 
sults secured  throughout  this  investigation  seem  to  indicate 
that  the  effect  of  light  summer  precipitation  on  the  Duty 
of  Water  are  practically  negligible,  so  far  as  the  water  re- 
quirements of  a  project  are  concerned. 

The  winter  precipitation  in  Idaho,  however,  is  more  of 
a  factor,  for  it  usually  furnishes  enough  moisture  to  bring 
the  crops  up  and  give  them  a  good  start  in  the  spring.  If 
these  data  are  used  in  determining  the  Duty  for  a  project 
where  spring  crops  must  be  irrigated  up,  due  allowance 
on  account  of  this  factor  must  be  made  in  the  allotment 
of  water  for  the  project. 

4.     Diversification  of  Farm  Crops. 

No  two  crops  have  exactly  the  same  water  requirements 
or  need  the  maximum  amount  of  water  at  the  same  time 
during  the  season.  If  a  farm  or  an  irrigation  projeit  is  de- 
voted to  only  one  crop  the  maximum  demand  for  water,  or 
in  some  cases  the  entire  need  for  the  season,  occurs  during 
a  brief  period.  In  such  cases  the  water  supply  of  a  project 
can  rarely  be  used  to  advantage,  for  the  major  portion 
of  a  continuous  flow  allotment  would  run  to  waste  out- 
side of  this  short  period.  By  diversifying  the  crops  on  a 


REPORT  OF  STATE  ENGINEER.  158 

farm  or  a  project  the  need  for  water  will  be  more  con- 
stant throughout  the  season  and  a  higher  Duty  and  Use 
of  Water  is  thereby  secured. 

5.     Use  of  Rotation. 

The  continuous  flow  method  of  delivery  should  give 
way  to  the  rotation  system.  Practical  irrigators  invariably 
realize  that  economical  irrigation  cannot  be  accomplished 
with  a  small  irrigation  head,  for  a  small  stream  dwindles 
away  before  it  has  flooded  across  the  field,  and  is  thus 
more  or  less  ineffective.  Large  heads,  on  the  other  hand, 
can  be  forced  across  a  field  quickly  and  made  to  do  thor- 
ough irrigation  in  a  much  shorter  time.  Crops  do  not  re- 
quire continuous  irrigation  any  more  than  a  man  requires 
a  continuous  drink  of  water.  The  results  of  the  investi- 
gation have  repeatedly  proven  conclusively  that  the  use 
of  comparatively  large  heads  results  in  a  saving  of  both 
time  required  for  the  irrigation  and  the  amount  of  water 
required  by  the  crops.  Large  heads  are  an  absolute  neces- 
sity with  porous  soils  in  order  to  permit  flooding  of  the 
surface  quickly  enough  to  prevent  abnormally  deep  perco- 
lation losses.  There  are  but  few  projects  where  rotation 
of  water  between  individuals  will  not  work  satisfactorily. 
This  is  particularly  desirable  where  a  project  consists  of 
small  holdings  with  consequent  small  allotments  per  unit. 
Botation  systems,  by  means  of  which  a  farmer  can  ex- 
change water  with  neighbors  and  use  larger  heads  for  short 
er  periods  are  now  being  used  in  several  Idaho  localities, 
and  the  saving  of  water  and  the  time  of  the  irrigator 
are  very  material.  An  ideal  system  of  rotation  requires 
that  water  be  maintained  in  the  main  canals  and  main  lat- 
erals continuously,  and  that  the  individuals  under  eacb 
lateral  should  have  access  to  a  good  sized  irrigation  head, 
probably  the  full  flow  of  the  lateral,  at  intervals  not  far 
ther  apart  than  every  14  days.  Tlhe  length  of  time  that 
the  user  should  be  allowed  to  retain  the  head  should  be 
dependent  upon  the  acreage  irrigated.  It  is  sometimes 
rather  difficult  to  inaugurate  rotation  systems  in  local! 
ties  where  the  irrigators  are  unfamiliar  with  the  benefits 
of  such  a  system,  but  a  locality  has  never  come  under  the 
observation  of  the  author  where  an  efficient  rotation  sys- 
tem has  been  in  use  for  two  year>s  in  which  the  irrigatorp 
desired  to  go  back  to  the  old  continuous  flow  system  of 
delivery. 


154:  REPORT  OF  STATE  ENGINEER. 

6-     Preparation  of  the  Land. 

An  even  application  of  irrigation  water  to  all  parts  of 
a  field  cannot  be  secured  with  rough,  uneven,  or  improper 
ly  leveled  land.  It  is  therefore  apparent  that  a  maximum 
crop  cannot  be  secured  on  land  that  is  rough  and  improp- 
erly leveled.  The  value  of. proper  leveling  and  the  effect 
of  improper  preparation  on  the  Duty  of  Water  is  so  evi- 
dent that  they  will  not  be  discussed  in  this  report.  Neither 
will  space  permit  of  an  extended  discussion  on  the  proper 
methods  of  preparing  land. 

Generally  speaking  the  land  should  be  so  leveled  that 
uniform  application  and  penetration  of  the  Avater  can  be 
secured.  In  order  to  obtain  the  above  water  should  never 
be  flooded  too  far  between  cross  ditches.  Prom  300  to 
(100  feet,  depending  upon  the  porosity  and  topography  of 
che  land,  is  usually  about  the  right  distance. 

7.     Kind  of  Crop. 

The  kind  of  crop,  whether  cultivated  or  uncultivated 
and  the  length  of  season  that  it  requires  water,  have  a 
very  direct  bearing  upon  the  amount  required.  Alfalfa 
requires  water  from  early  spring  until  late  fall,  as  do  the 
clovers  and  pasture  grasses,  and  has  been  found  to  require 
nearly  twice  as  much  water  during  the  irrigation  season 
as  the  spring  or  winter  grains,  which  require  it  for  but 
a  comparatively  short  season.  Alfalfa  has  shown  a  de 
cided  tendency  throughout  the  investigation  to  produce 
the  most  crop  where  the  most  water  has  been  applied.  It 
has  been  made  plain  that  water  should  never  be  left  stand 
ing  on  alfalfa  more  than  an  hour  or  two  if  the  best  results 
are  to  be  obtained.  No  more  should  be  applied  at  an  ir- 
rigation than  the  soil  will  readily  absorb.  Where  the  above 
method  of  irrigating  alfalfa  is  followed  it  has  been  found 
almost  impossible  to  reduce  the  yield  by  applying  too  much 
water.  The  yield  produced,  however,  is  in  but  few  cases 
proportional  to  the  amount  of  water  applied,  and  it  is 
doubted  whether  or  not  it  will  ever  be  found  feasible  to  ap- 
ply more  than  3  acre  feet  per  acre  to  alfalfa  or  pasture  on 
the  medium  clay  loam  soils. 

The  investigation  has  proven  that  grains  and  potatoes 
can  very  easily  be  over-irrigated.  Where  abnormal 
amounts  have  been  applied  to  grains  the  yields  have  always 
been  materially  reduced.  By  far  the  larger  number  of 
the  experiments  included  in  the  investigation  have  been 


REPORT  OF  STATE  ENGINEER.  155 

carried  on  with  the  spring  and  winter  grains,  and  these 
have  proven  that  there  is  no  doubt  but  that  it  will  rarely 
be  profitable  to  apply  more  than  one  and  one-half  acre 
feet  per  acre  to  grains.  The  above  applies  to  the  medium 
or  clay  loani  soils  only.  Where  grains  are  planted  on 
fertile  soils  less  than  the  above  amount  may  be  required. 
Where  as  much  as  3  acre  feet  per  acre  have  ben  applied 
to  spring  grains  at  the  Gooding  Experiment  Station  the 
yields  have  been  repeatedly  reduced  to  that  which  was 
produced  on  adjoining  plots  where  no  irrigation  water  was 
applied,  while  the  maximum  yield  was  produced  with  ap 
proximately  one  and  one-half  acre  feet  per  acre. 

A  cultivated  crop  such  as  corn,  garden  or  orchard  that 
can  be  cultivated  between  the  rows  will  require,  all  other 
things  being  equal,  considerably  less  water  than  an  un- 
cultivated crop  on  account  of  the  decreased  evaporation 
losses  induced  by  the  cultivation. 

The  experiment  on  the  Dunlap  orchard,  which  was  car- 
ried on  during  the  years  of  1911,  1912,  and  1913,  near  Twin 
Palls,  is  striking  proof  of  the  great  saving  of  moisture 
that  can  be  made  by  properly  cultivating  the  surface  soil. 
This  orchard  was  thoroughly  clean  cultivated  and  made 
to  all  appearances  a  maximum  growth  and  crop  of  fruit,  yet 
it  received  only  a  total  of  approximately  0.75  acre  feet 
per  acre  during  the  three  seasons,  1911  to  1913  inclusive. 
This  experiment  was  carefully  conducted  and  shows  con- 
clusively that  the  methods  used  by  the  Southern  California 
walnut,  orange,  and  lemon  growers  for  the  conservation 
of  moisture  by  thorough  surface  cultivation  will  be  very 
effective  if  carried  out  in  Idaho,  and  that  orchards,  if 
planted  on  a  deep  soil  of  medium  texture,  will  require  very 
small  amounts  of  irrigation  water  for  at  least  the  first  10 
years  of  their  growth.  The  Dunlap  orchard  was  seven 
years  old  and  produced  300  boxes  of  excellent  fruit  per 
acre  during  the  last  year  of  the  experiment,  with  a  total 
application  of  0.75  of  an  acre  foot  per  acre  in  three  years, 
with  an  average  annual  rainfall  of  approximately  12  in- 
ches. This  performance  seems  to  prove  that  this  orchard, 
no  matter  what  its  age,  will  never  require  more  than  1.5 
acre  feet  per  acre  during  any  one  season,  no  matter  how 
large  a  crop  of  fruit  it  can  be  made  to  produce.  This  ex 
periment,  and  many  others  included  in  the  Investigation* 
strongly  emphasize  the  value  of  surface  cultivation  as  a 
saving  of  water.  Where  clover  or  alfalfa  is  planted  as  a 


156 


REPORT   OF   STATE   ENGINEER. 


cover  crop  orchards  will  require  at  least  as  much  water 
as  alfalfa  when  grown  for  hay. 

8.     Fall  Plowing. 

Fall  plowing  should  always  be  recommended.  It  loosens 
up  the  soil  early  in  the  fall  and  renders  it  more  capable  of 
absorbing  winter  rains  and  reduces  the  run  off.  The  use 
of  fall  plowing  benefits  the  soil  and  irrigator  in  many 
ways.  The  fact  that  the  land  is  plowed  in  the  fall  and 
ready  for  crop  as  soon  as  it  has  dried  out  sufficiently  in 
the  spring  enables  the  farmer  to  plant  his  crops  early  and 
in  due  time,  which  he  might  have  been  unable  to  do  if  the 
land  had  to  be  spring  plowed.  Fall  plowing  thus  allows 
the  crop  to  start  off  early  in  the  spring  and  permits  it  to 
make  better  use  of  the  winter  precipitation,  and  a  greater 
yield  with  a  less  than  normal  quantity  of  water  is  usually 
secured.  The  turning  up  and  loosening  of  the  soil  in  the 
fall  is  also  a  decided  advantage,  for  the  extra  freezing  and 
thawing  that  takes  place  together  with  the  aeration  of  the 
soil,  sets  free  an  added  amount  of  plant  food  and  makes 
a  larger  yield  possible,  all  other  things  being  uniform. 

An  experiment  was  carried  on  at  the  Gooding  Experi 
ment  Station  during  the  season  of  1911  to  determine  the 
effect  of  fall  vs.  spring  plowing  on  the  Duty  of  Water  and 
yield  produced  with  the  results  which  are  shown  in  the 
following  table.  A  study  of  the  table  makes  it  apparent 
that  too  much  emphasis  cannot  be  placed  on  the  many  ad 
vantages  of  fall  plowing. 

Results  of  Fall  versus  Spring  Plowing  Experiment,  Gooding 
Experiment  Station. 


Yield  of  grain 

<*  ^ 

0 

c 

O         ^ 

+J    ^VM 

?0 

*£ 

Treatment  of  sub-plot 

5Si. 

Per 

Per 

*•£•= 

acre 

'53  S-  c 

ub^ 

«5* 

Q*« 

acre 

foot 

i    Feet 

l 
2 

.314 

.315 

Fall  plowed  minimum  irrigation  
Spring  plowed  minimum  irrigation  

.376 
.376 

41.18 
32.88 

109.5 

87.  5 

38.0 
38.0 

3 
4 

.314 
.314 

Fall  plowed  average  irrigation  
Spring  plowed  average  irrigation  

.962 
.962 

43.65 

39  77 

45.5 
41  4 

41.0 
41  0 

5 
6 

.304 
.305 

Fall  plowed  maximum  irrigation 

1  533 
1.533 

47.54 
45.26 

31.0 
29.5 

42.0 
42.0 

Spring  plowed  maximum  irrigation  

OTHER  FACTORS  WHICH  HAVE  A  BEARING  ON 
DUTY  OF  WATER  AND  IRRIGATION  IN  GEN- 
ERAL. 

Length  of  Season. 
The  length  of  the  irrigation  season  is  in  many  cases  fixed 


REPORT  OF  STATE  ENGINEER. 


157 


by  statute,  but  the  true  length  of  the  season  or  the  length 
of  time  that  crops-  actually  require  water  is  a  much  mooted 
question.  Many  canals  are  required  to  run  water  through 
out  practically  the  entire  year  for  domestic  purposes  and 
stock  water,  but  the  number  of  days  that  such  canals  run 
water,  or  the  amount  of  water  they  divert  at  such  times 
does  not  furnish  an  accurate  idea  of  the  water  require- 
ments of  the  crops  under  them.  The  Duty  of  Water  In- 
vestigation, as  carried  on,  however,  throw's  much  new  light 
upon  this  subject,  for  in  the  main  only  the  amounts  ac 
tually  applied  to  the  crops  have  been  considered.  In  order 
to  furnish  a  sound  basis  in  regard  to  the  proper  length  of 
the  irrigation  season  under  average  South  Idaho  condi- 
tions, the  number  of  days  that  elapsed  between  the  date  of 
beginning  the  first  irrigation  and  the  end  of  the  last  irri- 
gation of  the  season  of  all  of  the  individual  tracts  in- 
cluded in  this  investigation  is  shown  in  the  following 
table.  There  has  been  nothing  added  either  at  the  be- 
ginning or  end  of  the  irrigation  season  for  stock  water, 
and  the  table  should  be  found  very  dependable  as  the 
totals  given  show  the  true  length  of  the  season  that  crops 
require  water  under  Idaho  conditions. 

Table  Showing  Average  Length  of  Irrigation  Season  of  Plots  Included 
in  the  Four  Years'  Duty  of  Water  Investigation. 


to 

o  , 

0  0 

*>i 

^c 

Crop 

~-  ce  u 

&£ 

T'C'3 

rt  «-  o 

Sfl| 

1* 

rt  o  " 

U    £ 

u  bo.^f 

0) 

O  *i  .w 

I* 

|1I 

>  _!}  U 

Grains  

1910 

76 

3.6 

3 

46.0 

Alfalfa  and  Clover.  . 

1910 

27 

4.7 

0 

95.4 

Grains  

1911 

% 

2.1 

17 

35.5 

Alfalfa  and  Clover... 

1911 

34 

6.1 

1 

111.4 

Grains  

1912 

60 

3.7 

10 

39.7 

Alfalfa  and  Clover... 

1912 

25 

5.6 

0 

87.3 

Grains  

1913 

66 

3.1 

8 

48.9 

Alfalfa  and  Clover  .  .  . 

1913 

15 

5.1 

0 

96.5 

Maximum 
J  length  of 
!  irrigation 
season,  days 

Average  dates  of 
irrigation 

First 
irriga- 
tion 

Last 
irriga- 
tion 

87 
144 

May  27 
May  12 

July  16 
Aug.  12 

64 
%   142 

June  13 
May  14 

July  19 

Sept.   2 

61 
123 

June    9 
May  23 

July  18 
Aug.  18 

110 
119 

June    5 
May  16 

July  23 
Aug.  20 

*Excl«sive  of  plots  having-  one  irrigation  only. 

Proper  Amount  to  Apply  per  Irrigation. 

A  study  of  the  tables  included  in  this  re]H>rt  shows  that 
the  amounts  that  have  been  applied  to  the  various  tracts 
per  irrigation  have  varied  widely.  It  is  not  uncommon  to 
find  soils  that  are  so  impervious  that  they  will  barely  ab 
isorb  0.1  to  0.15  feet  in  depth  per  irrigation,  on  the  one 
hand,  or  soils  so  porous  that  they  can  be  made  to  absorb 


158  REPORT  OF  STATE  ENGINEER. 

from  1  to  3  feet  in  depth  per  irrigation  on  the  other  hand. 
The  investigation  has  made  it  plain  that  from  0.1  to  0.2 
feet  per  irrigation  is  rather  insufficient  if  economy  of 
water  is  desired,  for  the  moisture  forced  into  the  soil  does 
not  last  long  enough  between  irrigations,  thus  necessitat 
ing  more  irrigations  per  season.  As  an  unavoidable  loss 
from  evaporation  always  occurs  at  each  irrigation  it  is 
desirable  to  apply  as  few  irrigations  during  the  season 
as  will  be  required  to  maintain  a  sufficiently  high  moist- 
ure content  in  the  soil  for  good  plant  growth.  Impervious 
soil  can  usually  be  improved  by  the  addition  of  manure 
or  the  plowing  under  of  alfalfa  which  incorporates  more 
humus  into  the  soil  and  changes  its  nature,  after  which  it 
will  not  only  absorb  water  more  readily  but  will  retain 
it  longer.  It  is  a  singular  coincidence  that  the  same  pro 
cess  which  renders  imperviousi  soils  more  porous,  also  rend- 
ers porous  soils  more  impervious,  for  the  addition  of  hu- 
mus, either  decomposed  or  otherwise,  tends  to  fill  up  the  ex- 
cessive amount  of  pore  spaces  and  renders  this  soil  less 
porous. 

The  results  of  the  investigation  indicate  that,  generally 
speaking,  from  3  to  6  acre  inches  per  application  is  the 
correct  amount  to  apply,  and  that  impervious  soils  should 
he  so  manipulated  that  they  can  be  made  to  absorb  at  least 
the  lesser  amount,  while  the  porous  soils  should  be  so 
handled  by  using  large  irrigation  heads  that  they  can  be 
irrigated  with  not  over  6  acre  inches  per  application  if 
economy  of  water  is  desired. 

The  fact  that  a  head  of  one  cubic  foot  per  second  delivers 
almost  exactly  one  acre  inch  per  hour  makes  it  compara- 
tively easy  for  an  irrigator  to  determine  approximately 
how  much  water  he  is  applying  to  his  land  without  any 
difficult  mathematical  calculation.  It  is  hardly  consid- 
ered that  it  will  ever  be  practical  to  predetermine  just 
how  much  should  be  applied  per  irrigation,  and  then  to 
apply  this  amount,  no  more,  but  it  is  believed  that  intelli- 
gent and  economical  practice  demand  an  approximate 
knowledge  of  the  amount  that  is  being  applied. 

LOSSES  AND  WASTE  OF  WATER. 
The  individual  irrigator  is  most  concerned  with  the 
losses  or  waste  of  water  that  may  be  experienced  from 
four  principal  sources:  (1)  transmission  losses.  (2) 
evaporation  losses,  (3)  surface  waste,  (4)  deep  percola- 
tion waste. 


REPORT   OF   STATE   ENGINEER.  159 

Transmission  Losses. 

Those  losses  are  sometimes  far  greater  than  most  irri- 
gators  realize.  The  seepage  data  contained  in  this  report 
clearly  show  that  the  transmission  losses  of  an  irrigation 
project  between  the  point  of  diversion  in  the  stream  and 
the  point  where  it  is  delivered  to  the  farmer  may  range 
from  10  to  as  high  as  50  per  cent.  Where  storage  reser 
voirs  are  included  as  part  of  a  project  the  losses  experi- 
enced before  it  is  delivered  to  the  farmer  may  be  still 
greater  and  total  as  much  as  75  per  cent  of  the  amount 
diverted.  The  irrigator  himself  is  usually  most  concerned 
with  the  transmission  loss  in  his  own  individual  supply 
ditch  which  carries  the  water  from  the  point  of  delivery 
to  the  land.  These  supply  ditches  usually  average  from 
one-quarter  to  one-half  mile  in  length  and  where  one  sec 
ond  foot  or  less  is  carried  the  losses  in  them  may  amount 
to  as  much  as  20  to  30  per  cent  per  mile,  but  10  per  cent 
per  mile  would  be  a  fair  average  for  the  medium  soils. 
The  data  included  in  this  report  emphasize  the  desirability 
of  short  canals,  and  that  even  these  should  be  well  con 
structed  through  material  of  a  rather  impervious  nature 

Evaporation   Losses. 

Of  evaporation  losses  those  from  the  irrigated  fields  are 
the  ones  which  principally  concern  the  irrigator.  These 
are  more  or  less  of  a  constant  and  represent  a  loss  that 
is  rather  hard  to  overcome,  for  the  majority  of  the  evap 
oration  losses  from  the  fields  take  place  within  48  hours 
after  irrigation  water  is  applied  and  before  cultivation  of 
the  surface  to  reduce  the  losses  can  take  place.  Supple- 
mentary investigations  of  evaporation  loss  at  the  Good 
ing  and  Twin  Falls  Experiment  Stations  .show  that  where 
2  acre  feet  per  acre  is  used  during  the  season,  the  same 
having  been  applied  in  from  four  to  six  equal  irrigations, 
from  six  to  nine  acre  inches  of  it  are  almost  invariably 
evaporated  into  the  atmosphere,  without  having  transpired 
through  the  plants.  The  high  and  almost  unavoidable 
loss  from  evaporation,  a  large  portion  of  which  takes  place 
within  three  days  after  application,  emphasizes  the  desir- 
ability of  applying  as  few  irrigations  as  possible.  Inves- 
tigations* made  by  the  Irrigation  Investigations  Depart- 
ment sihow  that  the  evaporation  loss  from  soils  may  be  ma- 
terially reduced,  (1)  by  applying  the  water  in  rather  deep 
furrows,  and  (2)  by  the  maintenance  of  an  efficient  dust 
mulch  on  the  surface.  This,  of  course,  will  apply  more 

r^f     TTU-»-^v.4™.nv>+      QtlfiVinc,     13  nil  At?  *•>      XTrt         0  A  C 


160 


REPORT  OP  STATE  ENGINEER. 


particularly  to  orchards  and  other  clean  cultivated  crops. 
The  water  requirements  of  alfalfa  fields  can  be  materially 
reduced  by  disking  in  the  late  fall  or  early  spring.  This 
manufactures  a  sort  of  loose  non-conducting  layer  on  the 
surface  and  thereby  decreases  evaporation,  and  at  the  same 
time  renders  the  surface  so  much  looser  that  it  will  absorb 
more  of  the  moisture  which  is  received  through  natural 
precipitation. 

Surface  Waste. 

Many  theoretical  irrigatorsiorthose  unfamiliar  with  Idaho 
conditions  maintain  that  the  farmers  should  so  prepare 
their  fields  and  so  handle  their  water  that  no  surface  waste 
be  allowed  to  run  off.  This,  however,  is  not  feasible  in 
Idaho  at  the  present  time  if  the  value  of  labor,  land,  water 
and  crops  produced  be  taken  into  consideration,  and  an 
average  irrigator  is  surely  justified  in  allowing  a  small  per 
cent  of  waste  providing  the  same  cannot  be  economically 
prevented.  It  is  believed  that  the  average  waste  that  has 
taken  place  from  the  individual  fields  included  in  this  in- 
vestigation are  fair  and  normal,  and  that  they  approxi- 
mately equal  those  that  may  be  expected  in  average  irriga- 
tion practice  in  this  State.  The  following  table  has  been 
compiled  in  order  to  show  the  average  waste  that  has  taken 
place  from  the  tracts  included  in  the  investigation,  the  per- 
centages given  being  based  on  quantity  of  water  delivered 
to  the  land. 

Percentage  Wasted  of  Total  Amount  Applied. 


Crop 

Class  of  soil 

Number  of 
irrigations 

Percentage  of  waste 

Maximum 

Minimum 

Average 

Alfalfa  
Grain  
Alfalfa  
Grain  

Clay  loam  
Clay  loam  

302 
291 
147 

122 

55.7 
83.3 
24.8 
31.4 

0.0 
0.0 
0.0 
0.0 

19  1 

25.3 
1.8 
2-3 

Gravelly  
Gravelly  

This  table  gives  the  average  waste  from  several  hundred 
of  the  individual  tracts  that  were  included  in  the  Duty 
of  Water  investigation  during  the  4  years,  the  soils  and 
crops  being  divided  into  two  classes  for  convenience  and 
ready  comparison.  The  table  shows  that  over  one-half  of 
the  water  applied  to  grain  and  alfalfa  on  clay  loam  soils 
is  sometimes  wasted,  and  that  the  average  amount  wasted 
of  the  total  amount  applied  was  25.3  per  cent  for  grain 
and  19.1  per  cent  for  alfalfa.  While  the  above  percentage 


REPORT  OF  STATE  ENGINEER.  161 

of  waste  may  seem  high  to  many,  the  results  of  the  in 
vestigation  have  shown  them  to  be  a  fair  average.  The 
above  figures,  however,  are  based  on  the  result  from  single 
fields,  and  irrigators  should  not  be  allowed  to  waste  this 
percentage  from  their  entire  holdings.  Their  irrigation  sys- 
tems should  be  so  laid  out  that  as  much  as  possible  of  the 
waste  water  could  be  caught  up  and  used  over  again  on 
one  or  11101-0  fields  before  it  is;  finally  allowed  to  be  wasted 
off  the  farm.  It  is  safe  to  assume  that  the  average  farms 
of  Idaho  could  be  so  laid  out  that  waste  would  not  run 
directly  off  of  the  farm  from  over  one-quarter  its  area. 
Rather  steep  farms  of  small  area  would  naturally  waste 
more  water,  all  other  conditions  being  uniform,  than  the 
large  flat  farms  with  the  more  porous  soil.  Under  nor 
mal  Idaho  conditions,  however,  it  is  believed  that  all  water 
contracts  should  provide  for  a  sufficient  delivery  over 
and  above  the  actual  water  requirements  of  the  soils  and 
crops  so  that  the  irrigator  might  be  allowed  to  waste  a 
small  amount,  probably  between  seven  and  one-half  and 
twelve  and  one-half  per  cent  of  the  amount  delivered  to 
him,  and  still  retain  sufficient  for  his  crop  needs. 

This  is  not  a  very  serious  factor  when  a  whole  project  is 
taken  into  consideration  and  no  large  allowance  would 
have  to  be  miade  for  it,  for  a  large  amount  of  all  of  the  waste 
water  can  usually  be  caught  up  by  the  lower  laterals  and 
used  over  again.  A  larger  amount  of  the  waste  could  be 
caught  up  and  reused  on  the  larger  projects  than  could  be 
done  on  the  smaller  projects.  This  factor  is  one  that  must 
not  be  overlooked  when  designing  irrigation  projects.  All 
measurements  tabulated  in  this  report,  with  but  few  ex- 
ceptions, are  those  of  the  actual  amounts  retained  upon 
the  fields  in  question,  and  if  these  measurements  are  used 
in  alloting  water  to  a  new  project  care  must  be  used  to 
make  a  reasonable  allowance  for  the  unavoidable  waste 
that  each  individual  farmer's  water  is  subject  to. 

Deep  Percolation  Loss. 

The  abnormal  amounts  that  were  applied  to  some  of  the 
tracts  included  in  the  investigation  indicated  even  as  early 
as  the  first  year  of  the  investigation  that  the  losses  from 
deep  percolation  were  far  greater  than  most  irrigators 
realize.  This  seemed  true,  for  it  hardly  seemed  possible 
that  alfalfa  or  other  crops  could  utilize  and  transpire  any 
more  water  on  porous  soils  that  was  required  for  the 
same  production  of  the  same  crop  on  the  medium  soils.  The 


162  REPORT   OF   STATE  ENGINEER. 

rapid  rise  of  the  water  in  wells  during  the  irrigation  sea- 
son in  the  near  proximity  of  the  lands  irrigated  demon- 
strated that  such  large  losses  were  taking  place  from  this 
source  that  it  was  decided  to  conduct  a  simple  tank  ex 
periment  in  order  to  show  just  what  these  losses  amounted 
to  and  whether  or  not  the  crops  themselves  on  the  porous 
soils  actually  required  any  more  water  than  those  planted 
on  the  impervious  soils. 

A  tank  2  feet  in  diameter  and  6  feet  deep  was  construct 
od  and  installed  in  the  gravelly  soil  adjacent  to  one  of 
the  experimental  plots  on  the  Bate  farm  in  the  vicinity  of 
Bigby.  This  tank  was  buried  in  the  soil  in  an  upright 
position  with  the  top  flush  with  the  surface  and  was  care 
fully  filled  with  soil  in  as  near  its  normal  and  original 
position  as  the  same  could  be  placed.  The  tank  was  water 
tight  with  the  exception  of  one  place  in  the  bottom  which 
terminated  in  a  three-quarter  inch  galvanized  iron  pipe 
which  led  to  a  tub  in  a  curbed  pit  several  feet  away.  Al- 
falfa was  planted  on  the  tank  and  the  tank  was  irrigated 
during  one  entire  season  by  applying  the  same  amount  to 
it  that  was  applied  to  the  experimental  tract  and  also  to 
the  farmer  himself.  Seven  irrigations,  totaling  6.6  feet  in 
depth,  were  applied  to  the  experimental  tract  and  also  to 
the  tank.  The  alfalfa  £rew  luxuriantly  throughout  the  sea- 
son, showing  that  sufficient  moisture  was  retained  in  the 
6  feet  of  soil  of  the  tank  and  an  equivalent  of  a  depth  of 
5.5  feet,  or  83.5  per  cent  of  the  total  amount  applied,  was 
caught  in  the  tub  in  the  curbed  pit,  having  precolated 
from  the  tank. 

Mathematical  calculation  showed  that  the  tank  retained 
an  average  of  only  approximately  .15  feet  in  depth  at  each 
irrigation.  The  experiment  was  continued  during  the  fol 
lowing  year,  that  of  1912,  by  irrigating  the  alfalfa  in  the 
tank  every  time  it  needed  water  with  .15  feet  in  depth  per 
irrigation.  It  was)  found  that  ten  irrigations  were  required 
during  the  season,  representing  a  total  application  to  the 
tank  of  1.5  feet,  there  having  been  only  a  small  trace  of 
percolation  from  it.  The  alfalfa  grew  luxuriantly  through 
the  season,  was  cut,  thoroughly  cured  and  weighed,  and 
it  was  found  that  the  hay  which  grew  upon  the  tank  yield- 
ed at  the  rate  of  7.15  tons  per  acre,  which  proved  quite 
conclusively  that  the  soil  in  the  tank  had  sufficient  irri- 
gation for  the  production  of  a  profitable  crop. 


REPORT  OF  STATE  ENGINEER.  163 

Tn  view  of  the  above  and  other  observations  throughout 
the  investigatin  there  is  no  doubt  in  the  mind  of  the  author 
but  that  an  application  of  6  acre  inches  per  irrigation  to 
the  most  porous  of  soils,  which  is  probably  the  least 
amount  that  can  be  evenly  applied  under  present  practice, 
will  last  fully  as  long  between  irrigations  and  grow  just 
;is  much  crop  a.s  if  from  one  to  two  acre  feet  per  irriga- 
tion are  applied.  The  only  known  practical  means  of  ir 
rigating  porous  soils  so  as  to  eliminate  as  much  as  pos- 
sible of  the  needless*  deep  percolation  loss  is  to  prepare  these 
lands  for  irrigation  with  the  border  system  into  rather  nar 
row  lands  of  reasonable  length,  say  not  over  40  feet  wide 
and  300  feet  long,  and  irrigate  them  with  large  irrigation 
heads  of  from  5  to  10  second  feet.  On  all  but  the  most 
porous  of  land  this  type  of  a  system  and  size  of  irrigation 
head  will  successfully  and  economically  irrigate  the  lands 
with  an  average  application  of  not  over  6  acre  inches  per 
irrigation. 

From  the  above  discussion  of  the  losses  and  wastes  to 
which  irrigation  water  is  subject  it  will  be  seen  that  in 
abnormal  cases  where  a  large  amount  of  transmission 
loss,  evaporation  loss,  surface  waste  and  deep  percolation 
waste  are  experienced,  only  a  very  small  amount  of  the 
Avater  diverted,  and  probably  not  over  10  per  cent,  can 
be  used  beneficially  by  the  plants.  It  is  very  probable  that 
even  with  the  very  best  of  conditions  not  over  40  per  cent 
of  the  water  actually  diverted  from  a  river  or  source  of 
supply  is,  or  can  be,  used  beneficially  by  the  plants.  The 
above  discussions  are  given  so  much  in  detail  with  the 
hope  that  they  will  demonstrate  to  the  reader  that  the 
amount  of  loss  to  which  water  is  subject,  rather  than  the 
actual  requirements  of  the  crops,  are  the  real  factors  which 
have  fixed  the  water  requirements  of  a  project  in  the  past, 
und  with  the  idea  that  they  will  furnish  information  by 
means  of  which  the  abnormal  losses  that  are  not  being  ex- 
perienced in  some  localities  can  be  reduced. 

EFFECT  OF  LENGTH  OF  RUN  ON  DUTY  OF  WATER. 

Water  should  never  be  flooded  too  far  or  be  run  in  cor 
vugations  of  too  great  a  length  between  cross  ditches  on 
juiy  class  of  soil.  Where  water  is  run  too  far  between  cross 
ditches  even  application  is  not  obtained.  Too  much  is  usu- 
ally absorbed  on  the  upper  end  of  the  field  near  the  supply 


164 


REPORT   OF   STATE   ENGINEER. 


ditch,  or  too  little  at  the  lower  end  near  the  waste  ditch 
This  is  particularly  true  with  coarse  porous  soils,  there 
usually  being  an  abnormal  amount  of  deep  percolation 
Avaste  experienced  if  water  is  left  run  long  enough  to  thor- 
oughly irrigate  the  lower  end  of  the  fields.  It  is  concluded 
from  a  study  of  the  results  secured  in  the  entire  investi 
gation  that  it  is  never  feasible  to  run  water  between  cross 
ditches  a  greater  distance  than  from  300  to  600  feet,  de 
pending  upon  the  nature  of  the  crop,  the  topography  of 
the  land,  the  size  of  irrigation  head  used,  and  the  porosity 
of  the  soil.  A  series  of  experiments  were  conducted  on 
the  porous  soils  in  the  vicinity  of  Kigby  for  the  determina- 
tion of  the  effect  of  length  of  run  upon  the  amount  required 
per  irrigation.  It  was  found  that  an  application  of  from 
four  to1  nine  acre  inches  per  irrigation  lasted  fully  as  long 
between  irrigations  and  gave  equal  results  with  the  larger 
applications,  and  that  the  farther  water  was  flooded  the 
greater  the  amount  that  was  required  per  application.  The 
soils  under  consideration  were  very  porous  and  gravelly 
and  the  following  curve,  based  on  the  results  secured  from 
20  different  plots  of  varying  lengths,  shows  very  conclu 
sively  that  the  amount  required  per  irrigation  and  per  sea 
son  increases  very  rapidly  as  the  length  of  the  run  is  in- 
creased. These  plots  were  irrigated  with  heads  of  from 


y 


£es*?//j  o/ /%• 


CURVE  SHOWING  EFFECT  OF  LENGTH  OF  RUN  UPON  DUTY  OF  WATER. 


REPORT  OF  STATE  ENGINEER.  165 

3  to  5  second  feet,  and  were  only  fairly  well  prepared  for 
irrigation. 

EFFECT  OF  TOPOGRAPHY  ON  DUTY  OF  WATER. 

It  has  been  found,  all  other  things  being  equal,  that 
while  steep  slopes  and  rough  topography  in  general  affect 
the  amount  that  must  be  delivered  to  the  individuals  who 
fire  farming  the  land,  the  crops  grown  on  the  rough  or 
steep  land  do  not  actually  require  any  more  moisture  than 
where  grown  on  level  land.  A  larger  amount  of  waste 
water  is  unavoidable,  however,  where  steep  slopes  are  irri 
gated,  and  a  consequent  greater  amount  must  be  delivered 
to  the  irrigators  where  these  lands  exist.  Poorly  prepared 
land  absorbs  somewhat  more  water  than  where  well  pre 
pared,  for  the  low  spots  become  over  saturated  if  water 
is  held  on  lon«-  enough  to  wet  up  the  high  spots.  The  great- 
er portion  of  the  amount  that  is  wasted  from  the  lands  over 
and  above  the  amount  retained,  if  the  system  is  well  de 
signed,  can  usually  be  caught  up  and  measured  out  to  oth 
er  customers,  in  which  case  a  project  as  a  whole  will  re- 
quire but  little  more  water  if  the  lands  are  steep  but  well 
prepared  than  it  would  if  the  farms  had  only  a  small  01 
medium  slope. 

EFFECT   OF  SIZE  OF  IRRIGATION  HEAD. 

Where  the  individual  irrigators  are  able  to  command 
irrigation  heads  of  rather  large  size,  from  two  to  ten  sec- 
ond feet,  their  actual  requirements  in  acre  feet  per  acre 
per  season  are  usually  materially  reduced  over  the  require- 
ments where  the  small  but  continuous  flow  allotments  are 
used.  The  effect  of  a  large  irrigation  head  is  practically 
opposite  to  that  of  a  long  run  between  cross  ditches.  The 
larger  the  head  used  or  the  shorter  the  distance  betweeen 
cross  ditches,  the  less  the  net  water  requirements  willbedur- 
ing  the  season.  The  ability  to  command  a  large  irrigation 
head  has  many  advantages,  the  principal  ones  among  them 
being  the  saving  of  water  and  time  that  are  required  for 
irrigation.  The  savings  that  are  effected  by  the  use  of 
large  heads  are  more  material  where  porous  soils  exist,  for 
the  lands  can  be  flooded  so  quickly  that  abnormal  losses 
from  deep  percolation  are  eliminated.  The  ability  to  com- 
mand large  irrigation  heads  usually  necessitates  a  rota- 
tion system,  where  the  water  is  used  not  to  exceed  from 


166  REPORT  OF  STATE  ENGINEER. 

one-fourth  to  one-tenth  of  the  time  on  any  one  farm.  This 
allows  plenty  of  opportunity  for  other  necessary  farm  work 
and  permits  the  irrigator  to  give  his  undivided  attention 
to  the  irrigation  water  while  the  same  is  available,  which 
careful  attention  in  itself  invariably  results  in  a  material 
saving  of  water.  The  value  of  an  efficient  system  of  rota- 
tion and  the  ability  to  command  a  comparatively  large 
head  of  water  cannot  be  overestimated.  Rotation  systems 
however,  in  order  to  be  of  the  greatest  possible  value, 
should  be  somewhat  flexible.  Few  farmers  under  the  same 
project,  or  even  under  the  same  lateral,  have  the  same 
types  of  soil,  the  same  crop,  or  even  the  same  areas,  and 
the  systems  of  rotation  that  seem  to  give  the  best  satisfac- 
tion are  usually  those  where  a  continuous  flow  is  main 
tained  in  the  main  laterals  and  the  farmers  under  each 
lateral  are  allowed  to  work  out  the  rotation  system  best 
adapted  to  their  individual  needs.  The  kinds  of  crop  should 
determine  the  interval  between  irrigations,  and  each  user 
should  be  allowed  to  control  the  entire  flow  of  the  lateral 
ai  intervals  of  from  10  to  14  days,  the  length  of  time  he 
is  allowed  to  retain  water  at  each  interval  being  dependent 
upon  the  number  of  acres  owned. 

EFFECT  OF  INDIFFERENCE  OF  WATER  USERS. 

There  are  many  factors  which  have  a  decided  influence 
upon  the  Duty  of  Water,  but  in  actual  practice  the  value 
of  the  irrigation  water  may  have  a  greater  inflence  than 
all  other  factors  together.  Where  water  is  very  valuable 
and  is  settled  for  on  a  basis  of  a  certain  rate  per  acre  foot 
by  the  person  who  uses  it,  a  very  high  Duty  is  iiivariabty 
secured,  no  matter  what  may  be  the  climate,  the  class  of 
soil  or  the  crop  grown.  Under  the  above  conditions  all 
irrigators  soon  become  skillful.  Continuous  flow  allot- 
ments which  are  paid  for  on  a  flat  basis  per  acre  for  the  sea- 
son are  the  greatest  enemy  to  a  high  Duty  of  Water.  There 
are  but  few  other  commodities  that  are  delivered  to  the 
consumers  on  this  basis,  and  irrigation  water  should  not 
be,  for  the  flat  rate  of  payment,  independent  of  the  amount 
used,  places  a  premium  on  carelessness  and  waste.  With- 
out a  strong  underlying  incentive  to  save  water  a  high 
Duty  can  never  be  secured  on  any  project.  It  is  believed 
that  the  acre  foot  should  be  made  the  unit  of  measurement 
and  the  basis  of  all  contracts  and  decrees,  and  that  the 


REPORT  OF  STATE  ENGINEER.  167 

annual  maintenance  of  all  projects  should  be  based  upon 
the  acre  feet  actually  used  during  the  season  by  the  in- 
dividuals. It  is  believed  that  the  adoption  of  the  acre  foot 
as  a  basis  of  all  water  rights  and  the  sale  or  delivery  of 
water  by  the  acre  foot  would  go  further  toward  increasing 
the  Duty  without  decreasing  crop  production  than  any 
other  feature  that  could  be  inaugurated  at  this  time. 

EFFECT  OF  CONTINUOUS  FLOW  ALLOTMENTS. 

The  effect  of  continuous  flow  allotments  is  also  to  place 
a,  premium  upon  waste  and  the  careless  use  of  water. 
There  is  no  doubt  but  that  water  contracts  calling  for  a 
uniform  continuous  flow  are  radically  and  fundamentally 
wrong.  No  matter  how  much  a  user  may  waste  one  day 
lie  is  entitled  to  and  sure  of  the  same  amount  the  follow- 
ing and  succeeding  days.  The  adoption  of  a  quantity  basis 
such  as  a  Duty  expressed  in  acre  feet  per  acre  would  not 
jeopardize  old  water  contracts  or  priorities,  for  the  water 
right  holders  could  be  allowed  quantities  equivalent  to 
the  continuous  flow  to  which  they  are  now  entitled.  Tf 
water  was  distributed  on  a  quantity  basis,  measuring  de- 
vices would  be  installed  and  the  water  would  not  be  per- 
mitted to  run  to  waste  between  irrigations  as  is  usual 
where  the  uniform  continuous  flow  method  of  delivery  is 
in  vogue.  The  users  would  fear  lest  their  season's  allot- 
ment be  exhausted  before  the  end  of  the  season  and  would 
inaugurate  rotation  systems,  which  in  themselves  would 
increase  the  Duty  very  materially.  They  would  then  call 
for  only  enough  water  for  the  sufficient  irrigation  of  their 
crops  each  time,  after  which  it  would  be  to  their  own  in- 
terest to  see  that  the  headgate  be  shut  down  and  that  none 
be  let  run  to  waste  between  irrigations.  The  adoption  of 
such  a  system  as  above  outlined  would  work  out  to  the 
best  advantage  with  storage  systems. 

EFFECT  OF  TIME  OF  APPLICATION. 

The  stage  of  growth  at  which  irrigation  water  is  ap- 
plied, particularly  with  the  grains,  is  found  to  have  almost 
as  much  effect  on  the  crop  produced  as  the  total  amount 
of  water  applied.  It  has  been  found  that  one  good  irri- 
gation at  a  critical  period  of  the  plant's  growth  is  worth 
as  much  as  two  or  three  at  other  stages  of  its  growth.  The 
time  of  irrigation  does  not  seem  to  have  so  much  effect 


168  REPORT  OF  STATE  ENGINEER. 

upon  alfalfa  and  clover.  The  effect  of  time  of  application 
upon  the  yield  of  grain  produced  has  been  eliminated  from 
the  present  investigation  as  maich  as  possible  by  applying 
irrigations  on  the  comparable  plots  at  as  near  the  same 
time  as  possible. 

This  factor  has  been  shown  to  be  so  important  that  a 
Federal  Experiment  Station  has  been  started  at  Twin 
Falls  for  the  sole  and  specific  purpose  of  determining  at 
which  stage  of  groAvth  the  various  crops  should  be  irrigated 
in  order  to  give  the  best  results.  The  investigation  as 
a  whole,  however,  has  thrown  considerable  light  on  this 
subject.  In  a  general  way  it  seems  best  to  irrigate  alfalfa 
and  clover  before  and  after  each  cutting,  and  as  near  be- 
fore the  time  of  cutting  as  will  allow  the  surface  soil  time 
to  dry  out  sufficient  for  the  cutting  and  curing  of  the 
crop.  Alfalfa,  throughout  the  investigation,  has  been  in- 
clined to  produce  the  most  crop  where  the  most  water  was 
applied,  and  it  seems  best  to  keep  a  medium  but  uniform 
content  of  moisture  in  the  soil  of  an  alfalfa  field  through- 
out the  irrigation  season.  Only  as  much  as  will  be 
promptly  absorbed,  however,  should  be  applied,  for  water 
should  never  be  allowed  to  stand  on  alfalfa  for  any  length 
of  time.  With  the  grains  the  maximum  amount  of  water 
seems  to  be  required  at  the  booting,  jointing,  and  soft 
dough  stages  in  order  to  properly  fill  the  kernels.  Grain 
should  never  be  allowed  to  suffer  for  water  during  the 
blooming  or  soft  dough  stages,  or  shriveled  grain  will  re- 
sult. Potatoes  seem  to  require  a  medium  but  uniform 
moisture  content  in  the  soil  from  the  time  the  plants  ap- 
pear above  ground  until  just  before  maturity,  when  the 
water  should  be  turned  off  in  order  that  the  tubers  may 
ripen  properly.  Potatoes  require  practically  the  same 
amount  of  moisture  as  grains,  which  is  to  all  intents  and 
purposes  about  one-half  the  amount  that  is  required  by 
alfalfa,  clover,  and  pasture,  on  the  same  soil.  Potatoes 
should  never  be  allowed  to  dry  out  until  maturity  nor 
should  they  be  flooded,  for  the  soil  around  the  tubers  in 
the  hills  should  never  be  saturated.  They  should  be  irri- 
gated with  a  rather  deep  furrow  between  the  rows,  in 
which  case  only  a  sufficient  amount  for  good  growth  will 
reach  the  tubei-s  through  capillary  attraction.  Pastures 
require  light  but  frequent  applications  of  water  and  should 
never  be  allowed  to  dry  out  or  suffer  for  lack  of  water  if 
a  maximum  yield  is  to  be  secured.  Orchards  require  but 


REPORT  OF  STATE  ENGINEER.  169 

little  water  during  the  early  part  of  the  season  if  the  soil  is 
thoroughly  cultivated.  Bearing  orchards  require  the  ma- 
jority of  the  season's  supply  during  the  middle  and  latter 
part  of  the  season.  Where  large  areas  of  orchards  are 
found  a  larger  percentage  of  the  season's  supply  will  be 
needed  during  August  and  September  than  is  shown  by  the 
tables  contained  in  this  report. 

SUMMATION  OF  LOSSES  TO  WHICH  WATER  OF  A 
PROJECT  MAY   BE  SUBJECT. 

The  investigation  has  shown : 

(1)  That  seepage  and  evaporation  losses  in 
the  main  canal  of  a  project    may    range 
from  10  to  50  per  cent,  and  that  the  average 
for  most  projects  is  fully  30  per  cent  of  the 
total  amount  of  water  diverted. 

(2)  That  the  seepage  and  evaporation  losses 
in  the  internal  lateral  system  of  a  project 
range  from  5  to  15  per  cent  with  a  prob- 
able average  of  7.5  per  cent. 

(3)  That  the  deep  percolation  losses  on  the 
farm  range  from  10  to  80  per  cent  and  will 
probably  average  20  per  cent. 

(4)  That  the  surface  waste  from  a  farm  will 
range  from  5  to  50  per  cent  of  the  amount 
delivered,    and    should    average    approxi- 
mately 12.5  per  cent. 

(5)  That  the  evaporation  loss  of  the  amount 
retained  on  the  farm  will  range  from  6  to 
12  acre  inches,  or  from  10  to  50  per  cent  of 
the  amount  delivered. 

It  is  hardly  probable  that  the  water  which  is  delivered 
to  any  particular  individual  on  any  particular  project 
will  suffer  the  maximum  loss  from  each  and  all  of  the 
above  sources,  though  it  is  entirely  possible.  A  careful  study 
of  the  above  summary  shows  that  but  an  exceedingly  small 
part  of  the  amount  that  is  diverted  at  the  head  of  the  main 
canal  is,  or  ever  can  be,  absorbed  and  transpired  by  the 
plants.  The  above  losses  represent  actual  determinations 
for  the  most  part,  and  Avhile  they  can  never  all  be  elimi- 
nated, a  study  of  the  above  tabulation  shows  strikingly  that 
the  present  average  irrigation  practice  is  indeed  a  very 
wasteful  one. 

The  losses  in  the  internal  lateral  system   and  in   the 


170  REPORT   OF   STATE   ENGINEER. 


main  canal  of  a  project  might  be  almost  wholly  eliminated, 
liOAvever,  in  cases  where  the  saving  would  justify  the  ex- 
pense, by  lining  all  canals  -with  concrete  or  by  conveying 
the  water  in  pipes.  Deep  percolation  losses  and  surface 
waste  from  the  farm  might  also  be  almost  entirely  elim- 
inated by  careful  preparation  of  the  land  and  skillful  ap- 
plication of  the  water.  Evaporation  loss  that  takes  place 
from  the  fields,  however,  can  never  be  entirely  eliminated, 
but  may  be  materially  reduced  by  the  application  of  water 
in  deep  furrows,  and  thorough  surface  cultivation.  The 
above  discussion  should  clearly  indicate  that  in  by  far  the 
majority  of  cases  the  value  of  the  irrigation  water  has  a 
greater  influence  on  the  Duty  than  all  other  factors  to- 
gether, for  it  is  quite  plain  that  the  greater  part  of  .the 
water  that  is  now  diverted  is  lost  before  it  can  be  used 
by  the  plants  and  that  most  of  the  losses  that  irrigation 
water  is  now  subjected  to  can  be  eliminated  where  the  sav- 
ing will  justify  the  necessary  expense.  That  there  is, 
much  less  water  required  for  the  actual  use  of  the  plants 
than  most  irrigators  realize  is  amply  demonstrated  by  the 
large  yields  that  are  being  secured  with  very  small  quanti- 
ties of  water  in  Southern  California  and  other  places  wliere 
water  is  very  valuable.  Any  one  who  has  studied  irrigation 
conditions  elsewhere  will  be  compelled  to  admit  that  a 
large  amount  of  preventable  waste  is  now  being  experi- 
enced in  Idaho  and  other  places  where  water  is  cheap. 
Economic  conditions  do  not  warrant  saving  all  of  this 
waste  today,  but  there  is  no  doubt  but  that  the  time  is  fast 
approaching  when  better  systems  must  be  constructed. 

PROPER  DUTY  FOR  IDAHO  PROJECTS. 

The  results  of  the  investigation  indicate  that  a  normal 
Idaho  project  with  deep  medium  clay  loam  soils  should 
furnish  sufficient  Avater  so  that  2  acre  feet  can  be  retained 
upon  each  and  every  irrigated  acre  during  the  season.  That 
this  amount  should  be  delivered  under  a  rotation  system 
in  heads  of  such  size  that  economical  use  can  be  secured, 
and  that  where  a  project  is  devoted  one-half  to  grain  and 
the  other  one-half  to  alfalfa  or  crops  requiring  a  similar 
amount,  18.65  per  cent  of  this  two  acre  feet  should  be  de- 
livered during  May,  28.42  per  cent  during  June,  32.85  per 
cent  during  July,  16.78  per  cent  during  August,  and  2.32 
per  cent  during  the  first  one-half  of  September,  there  being 


REPORT  OF  STATE  ENGINEER.  171 

but  little  need  for  water  during  the  month  of  April,  and 
practically  none  after  the  middle  of  September.  It  has 
been  shown  that  there  must  be  delivered  to  the  farmer  ap- 
proximately 2.25  acre  feet  per  acre  at  the  farm  if  it  has  a 
normal  slope,  in  order  for  him  to  retain  two  acre  feet  upon 
the  land,  but  that  the  amount  delivered  must  be  increased 
where  steep  slopes  are  irrigated.  The  excess  that  is  deliv- 
ered over  and  above  the  two  acre  feet  per  acre  will  be  large- 
ly caught  up  in  lower  laterals  and  drain  ditches,  and  a  con- 
siderable part  of  it  can  be  delivered  again  to  other  users. 

Where  projects  consist  all  or  in  part  of  porous  soils,  or  of 
soils  with  porous  subsoil  lying  closer  to  the  surface  than 
six  feet,  more  than  2.25  acre  feet  per  acre  should  be  deliv- 
ered to  the  consumers,  the  amount  required  being  largely 
dependent  upon  the  porosity  of  the  soil. 

In  a  general  way  the  required  Duty  for  a  soil  can  be  de- 
termined for  any  crop  by  determining,  (1)  how  many  ir- 
rigations the  crop  will  require  during  the  season,  and  (2) 
the  amount  of  water  the  soil  will  require  per  irrigation. 

In  order  to  illustrate  how  the  data  contained  in  this  re- 
port can  be  used  for  determining  the  size  of  a  project  that 
can  be  irrigated  from  a  certain  definite  water  supply,  the 
following  purely  fictitious  project  will  be  used  as  an  ex- 
ample : 

Let  it  be  assumed  that  an  earth  reservoir  can  be  con- 
structed to  impound  the  total  annual  run-off  of  a  stream 
which  averages  150,000  acre  feet,  and  that  a  large  body 
of  good  deep  clay  loam  soil  with  an  average  topography 
can  be  irrigated  by  a  main  canal  20  miles  in  length. 

T(here  are  but  little  dependable  data  in  existence  in  re- 
gard to  reservoir  losses.  This  investigation  has  not  fur- 
nished any  light  on  the  subject.  An  annual  loss  of  20  per 
cent  of  the  gross  amount  of  the  run-off  from  seepage  and 
evaporation  in  the  reservoir  Avould,  however,  be  the  very 
least  loss  that  it  would  normally  be  safe  to  assume.  This 
would  render  available  80  per  cent  of  150,000  acre  feet,  or 
120,000  at  the  reservoir  outlet.  Seepage  losses  in  the  20 
miles  of  canal  and  in  the  laterals  should  then  be  deter- 
mined by  allowing  for  not  less  than  one  cubic  foot  of  loss 
per  day  from  each  square  foot  of  wetted  area  in  the  canals 
and  laterals  throughout  the  irrigation  season.  This  would 
in  the  above  case  amount  to  an  additional  loss  of  fully  20 
per  cent  in  transmitting  the  water  from  the  reservoir  to  the 


172  REPORT  OF  STATE  ENGINEER. 

individual  farms,  and  would  allow  of  a  delivery  of  96,000 
acre  feet  to  the  farms.  Assuming  that  the  soil  was  of  good 
character  and  not  inclined  to  be  porous,  2.25  acre  feet 
would  be  required  for  delivery  to  each  acre.  Ninety-six 
thousand  acre  feet  would  furnish  2.25  acre  feet  for  42,666 
acres.  If  there  was  an  average  of  two  acre  feet  retained 
on  each  acre,  0.25  acre  feet  per  acre  would  be  wasted  or  a 
total  of  10,666  acre  feet.  Fully  one-half  of  this  waste 
should  be  again  caught  up  and  measured  out  to  other  con- 
sumers and  would  furnish  two  acre  feet  per  acre  for  an  ad- 
ditional area  of  2,666  acres,  making  a  total  net  area  of 
45,332  acres  that  could  actually  be  irrigated  from  the  water 
supply.  The  survey  of  waste  land  showed  a  percentage 
unirrigated  of  8.06.  Assuming  that  10  per  cent  of  this 
project  Avould  never  be  irrigated  because  of  roads,  both 
county  and  private,  railroad  rights  of  way,  and  other  un- 
irrigated spots  of  all  kinds,  it  will  be  seen  that  water  would 
be  required  for  but  90  per  cent  of  the  gross*  area  of  the 
project.  This  would  increase  the  45,332  acres  to  50,369 
acres  as  the  gross  area  of  the  project  that  could  be  irri- 
gated under  normal  conditions  by  a  stream  with  a  gross 
annual  run-off  of  150,000  acre  feet,  provided  there  was  suf- 
ficient storage  capacity  to  retain  it  until  needed. 

The  investigation  has  demonstrated  the  adequacy  of  two 
acre  feet  per  acre  for  diversified  crops  on  the  better  class 
of  soil,  but  it  requires  careful  husbandry  to  render  this 
amount  adequate,  and  it  seems  very  evident  that  but  few 
projects  will  ever  exist  in  Idaho  where  an  allotment  of  less 
than  this  amount  would  be  justified. 

It  is  believed,  however,  that  the  amount  of  water  that 
will  produce  the  maximum  yield  of  crop  on  any  certain 
class  of  soil,  is  in  but  few  cases  the  proper  and  economic 
Duty.  It  is  very  evident,  and  the  author  wishes  to  strongly 
emphasize  the  fact,  that  the  cost  of  land,  of  water,  the 
value  of  the  crops  produced,  and  the  costs  of  producing 
them,  as  well  as  the  amount  of  water  that  will  produce  the 
largest  yield,  must  all  be  taken  into  consideration  when 
determining  the  Duty  for  any  project. 

The  largest  crop  has  been  produced  in  many  cases  where 
the  most  water  has  been  applied,  but  the  yield  has  been  in 
but  few  cases^  proportional  to  the  amount  of  water  re- 
quired, and  in  view  of  this  there  is  no  doubt  but  that, 
broadly  speaking,  one  would  be  justified  in  opening  up  a 
project  with  a  higher  Duty  of  water  in  places  where  water 


REPORT   OF   STATE   ENGINEER.  173 

is  very  valuable  and  land  comparatively  cheap,  than  where 
land  is  high  and  water  comparatively  inexpensive.  The 
allotment  of  the  proper  amount  of  water  for  an  irrigation 
project,  however,  is  a  very  serious  problem,  and  one  that 
must  be  given  the  most  careful  consideration,  for  it  is 
fully  as  vital  to  err  on  the  side  of  too  little  water  as  it  is 
on  the  side  of  too  much  water,  and  vice  versa. 

GENERAL  SUMMARY. 

1.  The  Duty  of  Water  Investigation,  of  which  the  pre- 
ceding pages  are  a  detailed  report,  has  covered  four  sea- 
sons, during  which  time  water  has  been  accurately  meas- 
ured on  529  individual  tracts  consisting  of  a  total  area  of 
slightly  over  3,600  acres.    These  tracts  have  included  all  of 
the  staple  crops  and  soils  common  to  South  Idaho.     The 
water  diverted  and  used  by  seven  different  canal  systems  in 
1011,  and  eight  different  systems  in  1912  wras  measured. 
Seepage  losses  have  been  determined  on  118  different  sec- 
tions of   different   canals  with   a  total   lineal   length    of 
287.31  males.    A  total  area  of  16,065.21  acres,  including  all 
or  parts  of  26  sections,  has  been  surveyed  for  the  deter- 
mination of  the  waste  or  non-irrigated  acreage  contained 
in  a  project.     In  addition  to  the  foregoing  measurements 
and  determinations  a  large  number  of  supplementary  in- 
vestigations have  been  made. 

2.  The  cost  of  the  investigation .  for  the  four  seasons 
from  its  inception  in  the  spring  of  1910  up  to  and  including 
January  1,  1914,  was  slightly  over  $55,000.00. 

3.  The  Duty  of  water  depends  upon  a  variety  of  factors 
which  are  in  the  apparent  order  of  their  importance :     (1) 
character  of  soil  and  subsoil,  (2)  fertility  of  soil,  (3)  cli- 
matic conditions,    (4)  diversification  of  farm  crops,    (5) 
use  of  rotation,   (6)  preparation  of  the  land,   (7)  kind  of 
crop,    (8)    fall  plowing,   and  other  factors  of  lesser  im- 
portance. 

4.  The  following  factors  and   conditions  tend   to  de- 
crease the  Duty:     (1)  porous  soil,   (2)   infertile  soil,  (3) 
cheap  water,  (4)  careless  use,   (5)  poorly  prepared  land, 
(6)  small  irrigation  heads,  (7)  poorly  constructed  leaky 
ditches,  (8)  continuous  flow  method  of  delivery,  (9)  lack 
of  cultivation,  (10)  large  acreages  of  alfalfa  and  pasture, 
and  other  crops  with  large  Avater  requirements. 

5.  The  following  factors  and   conditions  tend   to   in- 
crease the  Duty:     (1)    deep  soil  of  fine  texture,    (2)   an 


REPORT  OF  STATE  ENGINEER. 

underlying  strata  of  hard  pan,  (3)  expensive  water,  (4) 
careful  skillful  use,  (5)  well  leveled  land,  (0)  large  ir- 
rigation heads,  (7)  short  runs,  (8)  use  of  rotation  systems, 
(9)  diversification  of  crops,  (10)  well  constructed  irriga- 
tion systems  with  small  transmission  losses,  (11)  fall  ploAv- 
ing  and  intensive  surface  cultivation,  (12)  large  acreages 
of  winter  "Tain,  cultivated  crops  and  orchard,  and  other 
crops  of  low  water  requirements. 

6.  The  amount  of  water  required  by  a  project  depends 
upon:     (1)  the  Duty  of  water  at  the  land,   (2)   losses  in 
reservoirs  where  water  is  stored,   (3)   transmission  losses 
from  the  point  of  diversion  to  the  land  to  be  irrigated,  and 
(4)  the  proportion  of  a  project  that  is  ultimately  irri gated. 

7.  The  required  duty  for  a  crop  on  any  soil   can  be 
roughly  determined  by  ascertaining,  (1)  how  many  irriga- 
tions the  crop  will  require  during  the  season,  and  (2)  the 
amount  of  water  the  soil  will  require  per  irrigation. 

8.  The  Duty  far  projects  planted  to  diversified  crops 
on  the  average  clay  loam  soils  of  South  Idaho  should  be 
sufficient  so  that  two  acre  feet  per  acre  can  be  retained  on 
each  irrigated  acre. 

9.  A  sufficient  quantity  should  be  delivered  to  each  in- 
dividual over  and  above  the  two  acre  feet  so  that  he  may, 
if  unavoidable,  waste  not  to  exceed  12.5  per  cent  of  the 
water  delivered  to  him. 

10.  Fertile  soils  require  less  water  for  the  production  of 
the  same  crop  than  infertile  soils. 

11.  A  tight  impervious  soil  that  roots  can  penetrate  in- 
creases the  Duty. 

12.  More  water  is  required  Avhere  porous  subsoils  exist. 

13.  Gravelly  soil  may  require  two  or  more  times;  as 
much  water  as  the  medium  soil,  the  amount  required  de- 
pending upon  the  porosity  of  the  soil,  the  distance  water 
is  flooded  and  the  preparation  of  the  land  for  irrigation. 

14.  As  much  as  80  per  cent  of  the  water  applied  to 
gravelly  soil  is  sometimes  lost  to  the  use  of  the  crops  from 
deep  percolation. 

15.  Gravelly  soils  should  invariably  be  irrigated   by 
flooding  large  heads  of  water  short  distances. 

16.  The  light  summer  rainfall  common  to  South  Idaho 
has  but  little  effect  on  the  amount  of  irrigation  required. 

17.  Cultivated  crops,  all  other  things  being  equal,  re- 
quire less  water  than  uncultivated  crops,  as  the  loss  from 


REPORT  OP  STATE  ENGINEER.  175 

evaporation  can  be  reduced  by  thorough  surface  cultiva- 
tion. 

18.  Fall  plowing  tends  to  materially  increase  produc- 
tion and  decrease  water  requirements. 

19.  Grains  and  cultivated  crops  in  general  require  less 
irrigation  water  than  the  other  common  crops  of  South 
Idaho. 

20.  Winter  grains  require  less  water  than  spring  grains. 

21.  The  time  of  application  has  a  decided  effect  upon 
the  yield  of  grain. 

22.  Grains  require  the  largest  amount  of  water  at  the 
flowering  or  soft  dough  stages.    Alfalfa,  clover  and  pasture 
should  be  kept  uniformly  moist  throughout  the  season  and 
require  almost  exactly  twice  as  much  water  on  the  same 
soil  as  the  grains. 

23.  Alfalfa  has  a  decided  tendency  to  increase  in  yield 
as  the  amount  applied  is  increased  until  at  least  as  much 
as  four  acre  feet  per  acre  have  been  applied. 

24.  While  some  crops  increase  in  yield  as  the  amount  of 
water  applied  is  increased,  the  increase  in  yield  is  rarely 
proportional  to  the  increase  required  in  the  amount  of 
water. 

25.  The  average  waste  from  grain  fields  has  been  25.3 
per  cent  and  19.1  per  cent  from  alfalfa.     The  Duty  for  a 
project  should  be  so  fixed  that  12.5  per  cent  of  the  amount 
delivered  to  a  farm  may  be  wasted. 

26.  Diversification  of  crops  greatly  increase  the  Duty. 

27.  Very  little  water  is  required  for  a  project  either 
earlier  than  May  or  later  than  August. 

28.  The  average  length  of  the  irrigation  season  for  al- 
falfa for  the  four  years  of  the  investigation  was  97.6  days, 
and  42.5  days  for  grain. 

29.  The  need  for  water  is  not  constant  during  the  sea- 
son for  projects  with  diversified  crops.    About  one  per  cent 
of  the  season's  supply  is  required  during  April,  18  per  cent 
during  May,  28  per  cent  during  June,  32  per  cent  during 
July,  16  per  cent  during  August,  and  about  2.5  per  cent 
during  the  first  half  of  September,  after  which  there  is 
very  little  need  for  water.     This  is  shown  in  detail  by  the 
table  on  page  103. 

30.  Over  60  per  cent  of  the  total  supply  for  the  season  is 
required  by  a  project  devoted  to  diversified  crops  during 
the  months  of  June  and  July.  Owing  to  the  large  demands 


176  REPORT  OF  STATE  ENGINEER. 

of  the  crops  during  these  two  months  but  few  canals  can 
deliver  more  than  is  required  during:  this  period. 

31.  The  use  of  rotation  systems  and  large  irrigation 
heads  decrease  the  net  amount  of  water  required  during 
the  season. 

32.  Normal   canal  systems,   particularly   where   water 
is  inexpensive,  divert  far  more  water  than  is  actually  re- 
quired both  early  and  late  in  the  season. 

33.  The  amount  of  water  that  will  produce  the  largest 
yield  of  a  certain  crop  on  a  certain  soil  is  not  always  the 
economic  Duty. 

34.  The  value  of  land,  the  cost  of  water,  the  value  of 
the  crops  produced  and  the  cost  of  producing  them,  as  well 
as  the  amount  of  water  that  will  produce  the  largest  yield, 
must  all  be  taken  into  consideration  when  determining  the 
economic  Dutv  for  any  project. 

35.  Sufficient  water  for  the  production  of  profitable 
and  nearly  maximum  crops  must  be  delivered  to  the  indi- 
viduals in  order  that  a  project  may  be  successful,  but  a 
higher  Duty  is  justified  in  cases  where  water  is  very  val- 
uable and  land  comparatively  cheap  than  where  water  is 
cheap  and  the  land  is  valuable. 

36.  The  expression  of  seepage  losses  as  per  cent  of  loss 
per  mile  is  misleading. 

37.  Seepage  losses  should  be  expressed  as  the  unit  of 
loss  per  unit  of  wetted  area  of  canal  bed  per  unit  of  time. 

38.  Evaporation  losses  from  canals  are  negligible. 

39.  The  percentage  of  loss  is  extremely  high  in  small 
laterals  carrying  one  second  foot  or  less. 

40.  Losses  from  canals  in  medium  soil  range  from  0.5 
of  a  cubic  foot  to  1.5  cubic  feet  per  square  foot  of  canal  bed 
per  24  hours. 

41.  Porous  irrigated  land  above  a  canal  may  cause  it 
to  gain  instead  of  lose. 

42.  Canals  should  be  laid  out  through  compact  soils 
where  possible,  and  should  be  designed  with  as  small  a 
wetted  perimeter  as  possible. 

43.  Ninety  per  cent  of  a  normal  Idaho  project  is  irri- 
gated each  year.    The  total  waste  and  unirrigated  areas  sel- 
dom equal  10  per  cent. 

44.  Where  rotation  systems  are  used  the  interval  be- 
tween rotations  should  seldom  exceed  from  10  to  14  days. 

45.  There  are  now  at  least  163  electrically  operated 
pumping  plants  in  the  vicinity  of  Weiser  and  Payette. 


REPORT  OF  STATE  ENGINEER.  177 

46.  The  plants  tested  during    1913    pumped    varying 
amounts  of  water,  the  amounts  pumped  per  acre  ranging 
from  0.4  to  5.99  acre  feet.     The  costs  of  the  power  for 
pumping  varied  from  $.54  per  acre  foot  to  $6.50,  and  per 
acre  irrigated  from  f  1.77  to  $7.00. 

47.  There  is  not  sufficient  incentive  to  save  water  where 
a  flat  season  rate  is  paid  for  power. 

48.  The  investigation  indicates  that  the  cost  of  lifting 
water  over  100  feet  with  small  plants  is  at  present  prohibi- 
tive. 

49.  Serious  loss  and  waste  of  power  is  now  taking  place 
in  many  instances  due  to  faulty  design  and  cheap  careless 
installation  of  the  plants.    Small  and  medium  sized  plants 
should  develop  efficiencies  of  at  least  50  per  cent  and  only 
such  plants  as  can  be  guaranteed  to  do  this  or  better  should 
be  installed. 

50.  Successful  irrigation  in  Idaho  under  present  eco- 
nomic conditions  demands  that  at  least  two  acre  feet  per 
acre  be  supplied  for,  and  retained  upon,  each  irrigated  acre. 


M83628 


THE  UNIVERSITY  OF  CALIFORNIA  LIBRARY 


